Question

23. If x = -2 and x2 + y2 + 3xy = -5, then find y.
(a) -2 (b) 3 (C) -4 (d) 9.​

Answer 1

Plug in the value of x, and you get:

$(-2)^2 + y^2 + 3(-2)y = -5$

$4 + y^2 - 6y = -5$

$y^2 - 6y + 9 = 0$

$(y - 3)^2 = 0$

y = 3 (b)

Answer 2

Option b - 3

Step-by-step explanation:

Given : If x = -2 and $x^2 + y^2 + 3xy = -5$.

To find : The value of y ?

Solution :

The equation is $x^2 + y^2 + 3xy = -5$.

Substitute x=-2 in the equation,

$(-2)^2 + y^2 + 3(-2)y = -5$

$4+ y^2 -6y = -5$

$y^2 -6y +9=0$

$y^2-3y-3y+9=0$

$y(y-3)-3(y-3)=0$

$(y-3)(y-3)=0$

$(y-3)^2=0$

$y-3=0$

$y=3$

Therefore, the value of y is 3.

So, Option b is correct.

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