Question

Find the value of x^2 +y^2 if x+y is 11 and x-y is 3

Answer 1

Step-by-step explanation:

x^2+y^2={(x+y)^2+(x-y)^2}/2

={(11)^2+(3)^2}/2

=(121+9)/2

=130/2

=65

Answer 2

Answer:

65

Step-by-step explanation:

(x+y)²=11²

x²+y²+2xy=121 [eqn 1]

(x-y)²=3²

x²+y²-2xy=9 [eqn 2]

adding eqn 1 and 2

2x²+2y²=130

2(x²+y²)=130

x²+y²=130/2=65