Question

1. $(-8x^{4}y^{3})cdot(2x^{5}y^{2}) + 7x^{9}y^{5}$

Explanation:

Step1: Multiply the first - two terms

Use the rule of exponents \(a^m\times a^n=a^{m + n}\) and \(c\times d\times a^m\times b^n=(c\times d)\times a^m\times b^n\).
\((-8x^{4}y^{3})\cdot(2x^{5}y^{2})=(-8\times2)x^{4 + 5}y^{3+2}=-16x^{9}y^{5}\)

Step2: Add the result to the third term

\(-16x^{9}y^{5}+7x^{9}y^{5}=(-16 + 7)x^{9}y^{5}=-9x^{9}y^{5}\)

Answer:

\(-9x^{9}y^{5}\)