CPM Homework Help : GB8I Problem 3-115

Examine the rectangle at right. If the perimeter is $120$ , which equation below represents this fact? Once you have selected the appropriate equation, solve for $x$ .

$2x+5+6x-1=120$

$4(6x-1)=120$

$2(6x-1)+2(2x+5)=120$

$(2x+5)(6x-1)=120$

blank rectangle

right edge $2x+5$

bottom edge $6x-1$

Answer:

The equation for the perimeter is $c$ .

$2(6x − 1) + 2(2x + 5) = 120$

$(12x − 2) + (4x + 10) = 120$

$16x + 8 = 120$

$16x = 112$

$x = 7$