Answer:
I can't believe this guy above me has a verified answer and it is wrong.... anyway the true answer to this is 2. I checked it myself when I put 1 as the answer and got this question wrong, and it showed me the correct answer is 2 so don't believe the verified answer.
Step-by-step explanation:
Review Question #7:
The answer to this question is 2ft, not 1ft.
This is because:
So the width of the second rectangle can be represented by 10+2x, and the length of the second rectangle can be represented by 5+2x. Lets make 2x equal y to make things easier though. Because the product of both 10+2x and 5+2x is 84 square feet, we must multiply the two equations together first.
(10+y)(5+y)=84
This then equals:
50+10y+5y+y^2=84
Then add the like terms:
y^2+15y+50=84
Then set the equation to zero by subtracting 84 from both sides:
y^2+15y-34=0
From that, you can use the box method, or any method to get:
(y+17)=0 and (y-2)=0
Which would then simplify to:
y=-17 and y=2
However, we substituted y for 2x, so plug 2x into y:
2x=-17 and 2x=2
Then simplify from here:
x=-17/2 and x=1
The answer cannot be negative, so that means the answer is x=1, however, even though this is true, the answer is that 2ft was added to EACH SIDE, because the question was asking for what amount was added to each side.