MCQ 11 Mark
Assertion (A): $7 a^2\left(5 a^3+3 a^4 b\right)=35 a^5+21 a^6 b$
Reason (R) : If $x$ is any variable, and $m$ and $n$ are positive integers then $x^m \times x^n=x^{m+n}$.
Reason (R) : If $x$ is any variable, and $m$ and $n$ are positive integers then $x^m \times x^n=x^{m+n}$.
- ✓Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A)
- BBoth Assertion (A) and Reason (R) are true and Reason (R) is not the correct explanation
of Assertion (A). - CAssertion (A) is true but Reason (R) is false.
- DAssertion (A) is false but Reason (R) is true.
Answer
View full question & answer→Correct option: A.
Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A)
(a): $7 a^2\left(5 a^3+3 a^4 b\right)=\left(7 a^2\right)\left(5 a^3\right)+\left(7 a^2\right)\left(3 a^4 b\right)=35 a^{2+3}+21 a^{2+4} b=35 a^5+21 a^6 b$
$\therefore A$ is true.
By the law of exponents, $x^m \times x^n=x^{m+n}$.
$\therefore R$ is also true and R is the correct explanation of A .
$\therefore A$ is true.
By the law of exponents, $x^m \times x^n=x^{m+n}$.
$\therefore R$ is also true and R is the correct explanation of A .