How do you solve the system of equations $3 x - 4 y = - 24$ $3x-4y=-24$ and $x + y = - 1$ $x+y=-1$ ?

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Answer 1 · 2016-04-30T12:40:34

$x = - 4, y = 3$ $x=-4, y=3$

$3 x - 4 y = - 24$ $3x-4y=-24$

$x + y = - 1$ $x+y=-1$

If you multiply the 2nd equation by $4$ $4$ , you get

$3 x - 4 y = - 24$ $3x-4y=-24$

$4 x + 4 y = - 4$ $4x+4y=-4$

If you add up those two, you get

$7 x = - 28 \Rightarrow x = - 4$ $7x=-28 implies x=-4$

If you put $x = - 4$ $x=-4$ into one of the equations, you get

$- 4 + y = - 1 \Rightarrow y = 3$ $-4 + y = -1 implies y=3$

How do you solve the system of equations 3x-4y=-243x−4y=−243x-4y=-24 and x+y=-1x+y=−1x+y=-1?