Question

if x+y=1 and x-y=7,find the values of 5(x2+y2)​

Answer 1

Answer:

refer to the above attachment

Answer 2

EXPLANATION:-

x+y=1-----------------------eq-1

x-y=7-----------------------eq-2

x+y=1 (EQ-1)

x=1-y

Substitute x=1-y in eq-2

(1-y)-y=7

1-y-y=7

1-2y=7

-2y=6

y=-3

Substitute y=-3 in eq-1

x+y=1

x+(-3)=1

x-3=1

x=4

Hence the value of x is 4 and y is -3

Now let's find the value of 5(x²+y²)

==>5(x²+y²)

==>5{(4)²+(-3)²}

==>5(16+9)

==>5×25

==>125

Hence the value of 5(x²+y²) is 125