Question

-3x + 4y = -15 and 4x - y = -19

Answer 1

Answer:

x=-7, y=-9. (-7, -9).

Step-by-step explanation:

-3x+4y=-15

4x-y=-19

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y=4x-(-19)

y=4x+19

-3x+4(4x+19)=-15

-3x+16x+76=-15

13x=-15-76

13x=-91

x=-91/13

x=-7

4(-7)-y=-19

-28-y=-19

y=-28-(-19)

y=-28+19

y=-9

Answer 2

Answer:

$\boxed{\sf x=-7}$

$\boxed{\sf y=-9}$

Step-by-step explanation:

Solve for y → 4x - y = -19

$\sf y=19+4x$

Subtract 4x from both sides:

$\sf -y=-19-4x$

Multiply both sides by -1:

$\sf y=19+4x$

Now, Substitute y=19+4x to - 3x+4y= -15:

Let y=9+4x

$\sf -3x+4(19+4x)=-15$

$\sf 13x+76=-15$

Solve for x → 13x+76=-15

Subtract 76 from both sides:

$\sf 13x=-15-76$

$\sf 13x=-91$

Divide both sides by 13:

$\sf \cfrac{13x}{13} =\cfrac{91}{15}$

$\boxed{\sf x=-7}$

Substitute x= -7 into y=19+4x:

$\sf y=19+4x$

Let x= -7

$\sf y=19+4\times-7$

$\boxed{\sf y=-9}$

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