Question

i x + y = 7 and xy = 10
(ii) x - y = 11 and xy = 17.
Find the value of x2 + y2 when:​

Answer 1

Answer:

x+y=7 and xy=10

(x−y)

2

=(x+y)

2

−4xy=7

2

−4×10=49−40

∴x−y=

9

=±3