Questions · Page 2 of 2

1 Marks Question

Question 511 Mark
Write the coefficient of $x^2$ in $\sqrt{2} x-1$
Answer
Since $x^2$ is absent in given expression, therefore,
Coefficient of $x^2 = 0$
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Question 521 Mark
Write the coefficient of ${x^2}$ in $\frac{\pi }{2}{x^2} + x$
Answer
$\frac{\pi }{2}{x^2} + x$
The coefficient of ${x^2}$ in the polynomial $\frac{\pi }{2}{x^2} + x$ is $\frac{\pi }{2}$.
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Question 531 Mark
Write the coefficient of $x^2$ in $2 – x^2 + x^3$​​​​​​​
Answer
We have,Coefficient of $x^{2 }= -1$
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Question 541 Mark
Write the coefficient of ${x^2}$ in $2 + x^2 +x$
Answer
The coefficient of ${x^2}$ in the polynomial $2 + {x^2} + x$ is $1.$
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Question 551 Mark
Is the expression ${x^{10}} + {y^3} + {t^{50}}$, polynomial in one variable or not? State the reason for your answer.
Answer
${x^{10}} + {y^3} + {t^{50}}$
We can observe that in the polynomial ${x^{10}} + {y^3} + {t^{50}}$, we have x, y and t as the variables and the powers of x, y and t in each term is a whole number.
Therefore, we conclude that ${x^{10}} + {y^3} + {t^{50}}$ is a polynomial but not a polynomial in one variable.
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Question 561 Mark
Is the expression $y + \frac{2}{y}$, polynomial in one variable or not? State the reason for your answer.
Answer
$y + \frac{2}{y}$
We can observe that in the polynomial $y + \frac{2}{y}$ ,we have y as the only variable and the powers of y in each term are not a whole number.
Therefore, we conclude that $y + \frac{2}{y}$ is not a polynomial in one variable.
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Question 571 Mark
Is the expression $3\sqrt t + t\sqrt 2$, polynomial in one variable or not? State the reason for your answer.
Answer
$3\sqrt t + t\sqrt 2$
We can observe that in the polynomial $3\sqrt t + t\sqrt 2 $ we have t as the only variable and the
powers of t in each term are not a whole number.
Therefore, we conclude that $3\sqrt t + t\sqrt 2$  is not a polynomial in one variable.
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Question 581 Mark
Is the expression ${y^2} + \sqrt 2$, polynomial in one variable or not? State the reason for your answer.
Answer
${y^2} + \sqrt 2$
We can observe that in the polynomial ${y^2} + \sqrt 2 $, we have y as the only variable and the powers of y in each term are a whole number.
Therefore, we conclude that ${y^2} + \sqrt 2$  is a polynomial in one variable.
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Question 591 Mark
Is the expression $4{x^2} - 3x + 7{\text{ }}$, polynomial in one variable or not? State the reason for your answer.
Answer
$4{x^2} - 3x + 7{\text{ }}$
We can observe that in the polynomial $4{x^2} - 3x + 7{\text{ }}$
we have x as the only variable and the powers of x in each term are a whole number.
Therefore, we conclude that $4{x^2} - 3x + 7{\text{ }}$ is a polynomial in one variable.
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Question 601 Mark
Find a zero of the polynomial p(x) = 2x + 1
Answer
Finding a zero of p(x), is the same as solving the equation p(x) = 0
Now, 2x + 1 = 0 gives us $x=-\frac{1}{2}$
So, $-\frac{1}{2}$ is a zero of the polynomial 2x + 1 $$ $$ $$
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Question 611 Mark
Check whether –2 and 2 are zeroes of the polynomial x + 2
Answer
We have, p(x) = x + 2
Then p(2) = 2 + 2 = 4, p(–2) = –2 + 2 = 0
Therefore, –2 is a zero of the polynomial x + 2, but 2 is not the zero of the polynomial.
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Question 621 Mark
Evaluate $999^3$ using suitable identity.
Answer
We have, $(999)^3 = (1000 – 1)^3$
$= (1000)^3 – (1)^3 – 3(1000)(1)(1000 – 1)$
$= 1000000000 – 1 – 2997000$
$= 997002999$
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Question 631 Mark
Find the value of $p(t) = 4t^4 + 5t^3- t^2 + 6$ at $t = a.$
Answer
We have, $p(t) = 4t^4+ 5t^3 - t^2 + 6$
On putting $t = a$ in $p(t),$ we get,
$p(a) = 4 (a)^4 + 5 (a)^3 - (a)^2 + 6$
$= 4a^4 + 5a^3 - a^2 + 6$
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Question 641 Mark
Find the value of $p(x) = 5x^2 – 3x + 7$ at $x = 1$
Answer
The given polynomial is, $p(x) = 5x^2 – 3x + 7$
The value of the polynomial $p(x)$ at $x = 1$ is given by
$p(1) = 5(1)^2 – 3(1) + 7$
$= 5 – 3 + 7$
$= 9$
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Question 651 Mark
Expand $(4a – 2b – 3c)^2$
Answer
Using Identity $(x + y + z)^2 = x^2 + y^2 + z^2 + 2xy + 2yz + 2zx,$ we have
$(4a – 2b – 3c)^2 = [4a + (–2b) + (–3c)]^2$
$= (4a)^2 + (–2b)^2 + (–3c)^2 + 2(4a)(–2b) + 2(–2b)(–3c) + 2(–3c)(4a)$
$= 16a^2 + 4b^2 + 9c^2 – 16ab + 12bc – 24ac$
This is the required expansion.
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Question 661 Mark
Write $(3a + 4b + 5c)^2$ in expanded form.
Answer
Comparing the given expression with $(x + y + z)^2,$ we find that $x = 3a, y = 4b$ and $z = 5c.$
Therefore, using Identity $(x + y + z)^2 = x^2 + y^2 + z^2 + 2xy + 2yz + 2zx,$
we have $(3a + 4b + 5c)^2 = (3a)^2 + (4b)^2 + (5c)^2 + 2(3a)(4b) + 2(4b)(5c) + 2(5c)(3a)$
$= 9a^2 + 16b^2+ 25c^2+ 24ab + 40bc + 30ac$
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Question 671 Mark
Factorise: $\frac{25}{4} x^{2}-\frac{y^{2}}{9}.$
Answer
$a^2-b^{2 }$
$= (a+b)(a-b)\frac{25 x^{2}}{4}-\frac{y^{2}}{9}$
$=\left(\frac{5}{2} x\right)^{2}-\left(\frac{y}{3}\right)^{2}$
$=\left(\frac{5}{2} x+\frac{y}{3}\right)\left(\frac{5}{2} x-\frac{y}{3}\right)$
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Question 681 Mark
Find the products using appropriate identities: $(x - 3) (x + 5)$
Answer
We know the Identity $i.e., (x + a) (x + b) = x^2 + (a + b)x + ab,$
We have $(x – 3) (x + 5) = x^2 + (–3 + 5)x + (–3)(5) = x^2 + 2x \ – 15$
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Question 691 Mark
Find the products using appropriate identities: $(x + 3) (x + 3)$
Answer
We have the Identity: $(x + y)^2$
$= x^2 + 2xy + y^2.$
Put $y = 3$ in it,
we get $(x + 3) (x + 3) $
$= (x + 3)^2 $
$= x^2 + 2(x)(3) + (3)^2 $
$= x^2 + 6x + 9$
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Question 701 Mark
Find the degree of the polynomial: $2$
Answer
The only term here is $2$ which can be written as $2x^0 .$ So the exponent of $x $ is $0.$ Hence, the degree of the polynomial is $ 0.$
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Question 711 Mark
Find the degree of the polynomial : $2 – y^2 – y^3 + 2y^8$
Answer
The highest power of the variable is $8.$ Therefore, the degree of the polynomial is $8.$
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Question 721 Mark
Find the degree of the polynomial : $x^5 – x^4 + 3$
Answer
The highest power of the variable is $5.$ Therefore, the degree of the polynomial is $5.$
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1 Marks Question - Page 2 - MATHS STD 9 Questions - Vidyadip