how to solve 2x + 3y = -6 and 4x - y = 16

Question

How to solve it

Answer 1

From the first equation,

2X+3Y= -6
2X = -6 - 3Y
X = -(6 + 3Y)/2

So replace X value in the second equation,

4X - Y = 16
4(-(6+3Y)/2) - Y = 16
-12 - 7Y = 16
-7Y = 28
So Y= -4

Then We can find the X value from first or second equation,

2X + 3Y = -6
2X + 3x(-4) = -6
2X -12 = -6
2X = 6
X = 3

Comments

Or you can find values this way also,

First multiply the first equation by 2 both sides,
(2X + 3Y) x2 = -6 x2
4X + 6Y = -12

Then subtract that equation from the second equation,
4X + 6Y - (4X - Y) = -12 - 16
7Y  = -28
Y = -4

2X + 3Y = -6
2X + 3(-4) = -6
2X = 6
X=3