Question

If x+y = 1 and x- y = 7 .Find the value of 5(x^2 + y ^2). ​

Answer 1

Answer:

5x-2y=7 and xy=2,find the value of (5x+2y)^2 Get the ... (1) We have to find (5x+2y)² (5x+2y)² = (5x)² + (2y)² + 2× 5x× 2y

Answer 2

Given Equation:

x + y = 1 ______i

x - y = 7 ______ii

To Find:

The value of 5(x^2 + y ^2) ______iii

Solution:

By adding eq.i and eq.ii, we get

2x = 8

or, x = 4 ______iv

By putting eq.iv in eq.i, we get

4 + y = 1

or, y = 1 - 4 = -3

The value of x and y is 4 and -3 respectively.

By putting the value of x and y in eq.iii, we get

5(4^2 + -3^2)

= 5(16 + 9)

= 5(25)

= 125

Answer:

The value of 5(x^2 + y^2) is 125.