Solving and Plugging in x & y?

2 ⤊

If 4(x+y)(x-y)=40 and x-y=20, what is the value of x+y?

Please explain how to do this. thanks

2007-12-30 13:00:43 · 3 answers · asked by J 2 in Science & Mathematics ➔ Mathematics

4 (x + y) (20) = 40
x + y = 40 / 80
x + y = ½

2007-12-30 20:59:02 · answer #1 · answered by Como 7 · 1⤊ 0⤋

4(x+y)*20=40
then x+y=40/(4*20)=0.5

2007-12-30 21:03:53 · answer #2 · answered by Anonymous · 0⤊ 0⤋

4(x+y)(x-y)=40
4(x+y)(20)=40 x-y=20
4(x+y)=40/20
4(x+y)=2
x+y=2/4 or 1/2

2007-12-30 21:08:17 · answer #3 · answered by vkv 2 · 1⤊ 0⤋