Question

if x+y=1 and x-y=7 find the values of 2(x^+y^) and xy​

Answer 1

Given:

x+y=1 and x-y=7

To find:

if x+y=1 and x-y=7 find the values of 2(x^+y^) and xy​

Solution:

From given, we have,

x + y = 1 ...(1)

x - y = 7 ...(2)

solving equations (1) and (2), we get,

x = 4 and y = -3

Now consider,

The values of 2(x^+y^) and xy​

2(x^+y^) = 2 [4 + (-3)] = 2 [4 - 3] = 2

xy = 4 × -3 = -12

The value of 2(x^+y^) and xy​ are 2 and -12 respectively

Answer 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

Let's find the value of 2(x+y)

==>2{4+(-3)}

==>2×1

==>2

Now let's find the value of xy

x=4 and y=-3

==>4×-3

==>-12

Hence the value of 2(x+y) is 2 and the value of xy is -12