Please explain how to do this problem. The answer says the answer is 2.43 inches, but I don't get it.

Question

A school wants to take out an ad in the paper congratulating a basketball on a successful season. The area of the photo will be half the area of the entire ad. The photo is 7 in. wide and 5 in. long. How wide will the border be?

Answer 1

since you give no idea on the available space, that's hard to say. However, a border of 2.43 inches around a 5x7 photo will occupy an area of (5+2*2.43)(7+2*2.43) = 116.94 in^2, which is more than twice as big as the photo.

Answer 2

If you think about

Prentice Hall Algebra 1

9 - 6

then :

The area of the photo will be half the area of the entire ad.

Area of the photo = 7 * 5 = 35 in ^ 2

that is one half the area of the paper.

So area of the paper = 70 in ^ 2

Now you must solve equation :

( 7 + x ) ( 5 + x ) = 70

5 * 7 + 5 * x + x * 7 + x * x = 70

35 + 5 x + 7 x + x ^ 2 = 70

x ^ 2 + 12 x + 35 = 70 Subtract 70 to both sides

x ^ 2 + 12 x + 35 - 70 = 70 - 70

x ^ 2 + 12 x - 35 = 0

The solutions are :

- 6 - sqrt ( 71 ) = -14.43

and

sqrt ( 71 ) - 6 = 2.43

Wide cant be negative, so wide = 2.43 in

P.S.

If you don't know how to solve equation

x ^ 2 + 12 x - 35 = 0

then in google type :

quadratic equation online

When you see list of results click on :

Free Online Quadratic Equation Solver: Solve by Quadratic

When page be open in rectangle type :

x ^ 2 + 12 x - 35 = 0

and click option :

solve it

You will see solution step by step

Answer 3

Thanks Bosnian!

Answer 4

You're welcome.

Answer 5

Good work, but if x = 2.43, the border is only half that wide, if it surrounds the entire picture. I guess in this case it does not.

Answer 6

yeaaaaaasssss