SOLUTION: Can you please help me on this question: If the width of a rectangle is (x+7) cm and its perimeter is (8x + 12)cm. The length of the rectangle is 20cm. What is the area of the rect

Algebra ->  Rectangles -> SOLUTION: Can you please help me on this question: If the width of a rectangle is (x+7) cm and its perimeter is (8x + 12)cm. The length of the rectangle is 20cm. What is the area of the rect      Log On


   

Question 530107: Can you please help me on this question: If the width of a rectangle is (x+7) cm and its perimeter is (8x + 12)cm. The length of the rectangle is 20cm. What is the area of the rectangle?.
Found 2 solutions by nerdybill, Math_prodigy:
Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
Can you please help me on this question: If the width of a rectangle is (x+7) cm and its perimeter is (8x + 12)cm. The length of the rectangle is 20cm. What is the area of the rectangle?.
since
perimeter = 2(width + length)
8x+12 = 2(x+7 + 20)
8x+12 = 2(x+27)
4x+6 = x+27
3x+6 = 27
3x = 21
x = 7
.
Now, we can calculate width:
x+7 = 7+7 = 14 cm
.
area:
width*length
14*20 = 280 square cm

Answer by Math_prodigy(24) About Me  (Show Source):
You can put this solution on YOUR website!
2(x+7)+2*20=perimeter
2(x+7)+2*20=(8x+12)
2x+14+40=8x+12
6x=42
x=7
width is x+7=7+7=14
area is 20*14=280 cm^2