25+ POINTS WILL MARK BRAINLIEST
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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
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