Question

I got 2 it’s wrong so I’m not sure what step I missed

Answer 1

Given:

`\begin{gathered} a^2-7a-8 \\ a=-2 \end{gathered}`

Solution:

To evaluate the expression, we will substitute the value of -2 to a.

`\begin{gathered} a^2-7a-8 \\ a=-2 \\ (-2)^2-7(-2)-8 \\ \end{gathered}`

Now that we have substituted -2, we will perform the operations in between.

Since we are given a quadratic equation, we have to deal with the exponent.

Negative to raise to two is also equal to -2 multiplied by itself.

We will have:

`=(-2)\cdot(-2)^{}-7(-2)-8`

A negative number multiplied by another negative number will become a positive number.

Negative 2 multiplied by negative 2 is equal to positive 4.

`=4-7(-2)-8`

Now, for -7a we will have -2 multiplied by negative 7. It will become positive 14.

`\begin{gathered} =4-7(-2)-8 \\ =4+14-8 \end{gathered}`

After that, we will add 4 and 14 then subtract -8.

`\begin{gathered} =4+14-8 \\ =18-8 \\ =10 \end{gathered}`

ANSWER: 10