Question

If x²+y²=75 & xy = 35,then find x+y

Answer 1

$(x + y) { }^{2} = x ^{2} + y ^{2} + 2xy$
$(x + y) ^{2} = 75 + 2 \times 35$
$(x + y) {}^{2} = 75 + 70$

$(x + y) { }^{2} = 145$
$(x + y) = \sqrt{145}$

Answer 2

Given: x² + y² = 75 and xy = 35

To find: x + y

Identity to be used: (x + y)^2 = x^2 + 2xy + y^2

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

(x + y)^2 = 75 + 2*35

(x + y)^2 = 75 + 70

(x + y)^2 = 145

x + y = √145

x + y = 12.04

Hope it helps :)