When substituting, you want to take the y value from one equation and plug it into the y variable in the other equation to find the x value. When you find the c value, you plug the number into one of the equations to get your y value.
I cannot see the picture ?
P=2l+2w
W=7+3l
So substitute into the original equation
P=2l + 2(7+3l)
78=2l +14 + 6l
-14 -14
—————-
64=8l
8=length
W=7+3l
= 7+3(8)
=7+24
=31
Check your work
Perimeter=8+8+31+31
=78
Hope this helps
Answer:
B 39.75
Step-by-step explanation:
7.5x5.3=?