Question

25+ POINTS WILL MARK BRAINLIEST

Answer 1

Answer:

X=12.5

Step-by-step explanation:

3x+3x+15

If it equalls 90 then write it as 6x+15=90

Now isolate X.

6x+15=90

6x=75

x=12.5

CHECK UR WORK

(3*12.5)+(3*12.5)+15=90

37.5+37.5+15=90

75+15=90

90=90

Answer 2

Answer:

Step-by-step explanation:

perimeter of rectangle=a+b+c

=3x+3x+15

=6x+15

if perimeter of rectangle is 90,

perimeter=a+b+c

90=3x+3x+15

90-15=6x

75/6=x

12.5=x