Question

Multiply $-2^3{a}^{2}b$ by $5a^3{b}^2$ and verify your result for

$a=2$ and $b=3.$

Answer 1

$-2^3{a}^{2}b\times 5a^3{b}^2=(-2^3\times 5)\times (a^2\times a^3\times b\times b^2)$

$=-8\times 5\times a^{(2+3)}\times b^{(1+2)}$

$=-40a^5{b}^3$

When $a=2$ and $b=3$, we get:
$\text{L.H.S}$ $=-2^3{a}^{2}b\times 5a^3{b}^2=(-2^3\times 2^2\times 3)\times (5\times 2^3\times 3^2)$

$=-8\times 4\times 3\times 5\times 8\times 9$

$=-34560$

$\text{R.H.S.}$ $=-40a^5{b}^3=-40\times 2^5\times 3^3=-34560$

Hence, the result is verified.