Question

Question 12

Product of $6a^2-7b+5ab$ and $2ab$ is
a) $12a^{3}b-14a{b}^2+10ab$
b) $12a^{3}b-14a{b}^2+10a^2{b}^2$
c) $6a^2-7b+7ab$
d) $12a^{2}b-7a{b}^2+10ab$

Answer 1

b) $12a^{3}b-14a{b}^2+10a^2{b}^2$
$\to$Required product = $2ab\times (6a^2-7b+5ab)$
​​​​​​​This is product of a trinomial by a monomial, so we multiply monomial with each term of the trinomial.
$\therefore 2ab\times (6a^2-7b+5ab)=2ab\times 6a^2+2ab\times (-7b)+2ab\times 5ab=12a^{3}b-14a{b}^2+10a^2{b}^2$