Question 1004773
L= 2W
(2W+4)(W-3)= 100
-----------------------
Solve for W:
(W-3) (2 W+4) = 100
---------------------------
Expand out terms of the left hand side:
2W^2-6W+4W-12 = 100 Add subtract on left:
2W^2-2W-12= 100
Divide both sides by 2:
W^2-W-6 = 50 Fa
Add 6 to both sides:
W^2-W = 56
Subtract 56 on both sides:
W^2-W-56= 0 Factor the equation: 7*8= 56 and 8-7= 1
(W-8)(W+7)= 0
Split into 2 equations:
W-8= 0 or W+7= 0
W= 8 or W= -7 Toss the -7, we are not looking for a negative number.
Our width is 8. Proof:
(2W+4)(W-3)= 100
((2*8)+4)(8-3)= 100
20*5= 100
100=100 We've got the right answer