Question

Simplify.(y-8)^2-7(y-8)

Answer 1

The first thing to do to simplify this expression is to expand the term that is squared:

$\begin{gathered} (y-8)^2-7(y-8) \\ (y-8)\cdot(y-8)-7(y-8) \\ (y^2-8y-8y+64)-7(y-8) \\ (y^2-16y+64)-7(y-8) \end{gathered}$

Then, we can calculate the product of the second term of the expression:

(It's important to note the change in the signal: -7 times -8 is +56)

$(y^2-16y+64)-7y+56$

Now, we can sum the terms with the same exponent:

$\begin{gathered} y^2-16y+64-7y+56 \\ y^2-23y+120 \end{gathered}$

So the simplified expression is y2 - 23y + 120