Answer:
C) The perimeter of the rectangle is (10x + 18) units.
Step-by-step explanation:
First we will find the length by dividing the polynomials.
We first put the dividend, 4x²+39x-10, under the box. The divisor, x+10, goes on the outside of the box (to the left).
We divide 4x² by x; this is 4x. We put 4x above 39x in the quotient.
Next we multiply back through by 4x:
4x(x+10) = 4x²+40x. This goes under 4x²+39x in the dividend. We subtract, giving us -1x. We then bring down the -10, giving us the expression -1x-10.
We divide -1x by x. This is -1. This goes beside the 4x in the quotient. We multiply back through by -1:
-1(x+10) = -1x-10. This goes under the -1x-10 in the work. Subtracting cancels both of these, leaving us with the quotient 4x-1.
This is not the same as the width, so the rectangle is not a square. The length was not 2x-5.
The perimeter is found by adding
(4x-1)+(4x-1)+(x+10)+(x+10)
Combining like terms, we have
4x+4x+x+x-1-1+10+10
10x+18 is the perimeter.
