I think its he didnt eliminate the same variables
Answer:
p=18x+4
a=20x^2+17x-63
a=1350
Step-by-step explanation:
Given:
l=5x-7
w=4x+9
Required:
Area of the rectangle=?
Perimeter of the rectangle=?
If x = 9 inches what is the area of the shape=?
Formula:
a=l*w
p=2(l+w)
Solution:
p=2(l+w)
p=2(5x-7)+2(4x+9)
p=10x-14+8x+18
p=10x+8x+18-14
p=18x+4
a=l*w
a=(5x-7)(4x+9)
a=20x^2+45x-28x-63
a=20x^2+17x-63
Area of the shape if x=9in
a=20x^2+17x-63
a=20(81)+17(9)-63
a=1620+153-63
a=1413-63
a=1350
Exponent way n
exponetional way
