Question

if x+y=5 and x-y=4,find the value of xsquare-ysquare

Answer 1

Answer:

x²- y² = 20

Step-by-step explanation:

Using (a+b)(a-b) = a² - b²

x²- y² = (x+y)(x-y)

         = 5 x 4

         = 20

Answer 2

Answer:

(x-y)^2=(x+y)^2-4xy

=(5)^2-4(4)

=25-16

=9

x-y=(+ or -) 3