Question
Solve the following quadratic equation by factorization.
x2 + x – 20 = 0
x2 + x – 20 = 0
✓
Answer
$\begin{array}{l}
x^2+x-20=0 \\
\Rightarrow x^2+5 x-4 x-20=0 \\
\Rightarrow x(x+5)-4(x+5)=0 \\
\Rightarrow(x+5)(x-4)=0 \\
x+5=0 \Rightarrow x=-5 \\
x-4=0 \Rightarrow x=4 z
\end{array}$
Hence, $x=-5$ and $x=4$ are roots of the equation.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
The minute hand of a clock is 12cm long. Find the area swept by in it 35 minutes.
The length of tangent from a point A at a distance of $5\ cm$ from the centre of the circle is $4\ cm$. What is the radius of the circle?
→$\triangle D E F \sim \triangle M N K$, If $D E=5$ and $M N=6$, then find the value of $A (\triangle DEF ): A (\triangle MNK )$
→If one die is rolled then find the probability of each of the following events.
(i) Number on the upper face is prime
(ii) Number on the upper face is even.
(i) Number on the upper face is prime
(ii) Number on the upper face is even.
Solve the following quadratic equation by completing square method:
$x^2+3 x+1=0$
→$x^2+3 x+1=0$
What values of $x$ will make $DE\ ||\ AB$ in the given figure?
→Write the standard form of a linear polynomial with real coefficients.
A spherical ball of iron has been melted and made into smaller balls. If the radius of each smaller ball is one-fourth of the radius of the original one, how many such balls can be made?
Prove the following identities:
$\cos^2\theta-\frac{1}{\big(1+\cot^2\theta\big)}=1$
→$\cos^2\theta-\frac{1}{\big(1+\cot^2\theta\big)}=1$
Define value of polynomial at a point.