If 5x + 3y=4 and 5x-3y= 2, what is the value of (25x\(^2\) -9y\(^2\))?

LamestAmos

1 year ago

You can also solve this easier with difference of 2 squares where
a^2 - b^2 = (a+b)(a-b)

Applying,

25x^2 - 9y^2 = (5x + 3y)(5x - 3y)

Using substitution,

= (4)(2)

= 8

ruthdoosuur

4 months ago

Difference of Two Squares (5x+3y)(5x-3y) = (4)(2) = 8