Question

If (x2 – y2, x + y) = (–7, 7), then the value of x + 2y is

Answer 1

Step-by-step explanation:

given equation (x2-y2, x+y)=(-7,7)

equate on both sides

x2-y2=-7

x+y=7

x^2 -y^2=-7

it is in form a^2 -b^2 =(a+b)(a-b)

now

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

(x+y)(x-y) =-7

7(x-y) =-7

x-y= -1

now

x-y=-1

x+y=7

.............

2x=6

x=3

now substitute x=3 in x+y=7

3+y=7

y=7-3

y=4

x=3,y=4

now x+2y

3+2(4)

3+8

=11 is answer obtained

Answer 2

SOLUTION,

Here we can write,

2x - 2y= -7. & ......,........(i)

x + y = 7..........................(ii)

multiply eqn (ii) by 2, we get

2x + 2y = 14 ...............(iii)

Now, add eqn (i) & (iii), we get

2x - 2y +2x + 2y = -7 + 14

4x = 7

x = 7/4

Now put the value of x in (i),

2×7/4 + 2y = 14

7/2 + 2y = 14

2y = 14 - 7/2

2y = 28/2 - 7/2

2y = 21/2

Now find the value of

x + 2y = 7/4 + 21/2

= 7/4 + 42/4

= 49/4

Hence, the value of x + 2y = 49/4

I HOPE THIS HELP YOU.

MARK AS BRAINLIST.

STAY HOME STAY SAFE.