Question

Simplify:
a) If x + y = 4 and xy = 2, find the value of x2 + y2
b) Find the value of the expression using perfect square trinomial method:
81x2 + 16y2– 72xy when x = 2/3 and y = 3⁄4

Answer 1

Answer:

(a) x+y=4

B.s.q.

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

x^2+y^2+2xy=16

x^2+y^2+2×2=16

x2+y^2=16-4

x^2+y^2=12.

is correct answer.

Step-by-step explanation:

(b).81x^2+16y^2-72xy

81×(2/3)^2+16(3/4)^2-72×2/3×3/4

81×4/9+16×9/16-72×1/2

9×4+9-36

36+9-36

9..

is correct answer.

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