Question

Multiply the monomial by the binomial and find the value for x = −1, y = 0.25 and z = 0.05: 15y²(2 − 3x)

Answer 1

To find the product, we will use distributive law as follows:

\[15 y^2 \left( 2 - 3x \right)\]

\[ = 15 y^2 \times 2 - 15 y^2 \times 3x\]

\[ = 30 y^2 - 45x y^2\]

Substituting x =\[-\] 1 and y = 0.25 in the result, we get: 

\[30 y^2 - 45x y^2 \]

\[ = 30 \left( 0 . 25 \right)^2 - 45\left( - 1 \right) \left( 0 . 25 \right)^2 \]

\[ = 30 \times 0 . 0625 - \left\{ 45 \times \left( - 1 \right) \times 0 . 0625 \right\}\]

\[ = 30 \times 0 . 0625 - \left\{ 45 \times \left( - 1 \right) \times 0 . 0625 \right\}\]

\[ = 1 . 875 - \left( - 2 . 8125 \right)\]

\[ = 1 . 875 + 2 . 8125\]

\[ = 4 . 6875\]