Algebra: Find the value of A so that (A + B)x + (A - B)y = 4

[megan0430]

Find the value of "A" so that (A + B)x + (A - B)y = 4 and x + y = 1 are the same lines.

Please help me. Thank you so much!

 

[Mrspi]

Re: Algebra PROBLEM! HELP PLEASE <3

Find the value of "A" so that (A + B)x + (A - B)y = 4 and x + y = 1 are the same lines.



PLEASE HELP ME.
THANK YOU SOO MUCH!

If they are the same lines, then they have the same slope, and the same y-intercept.

I'd try putting each equation into slope-intercept form.

(A + B) x + (A - B) y = 4
(A - B) y = 4 - (A + B)x
y = 4 / (A - B) - [(A + B) / (A - B)] x
y = - [(A + B) / (A - B)] x + 4 / (A - B)

x + y = 1
y = -x + 1

Ok...in order for these lines to be the same,

the slopes must be equal
-[(A + B) / (A - B)] = -1
and the y-intercepts must be equal
4 / (A - B) = 1

You've got two equations in two variables....

I hope this helps you.