Question

7x + 2y = -1 3x – 4y = 19

Answer 1

Answer:  Y = - 4 & x = 1

Step-by-step explanation:

Systems of linear equations: We will solve this using substitution but you can use 2 more ways.

7x + 2y = -1

2x - 4y = 19

Leave X  alone first: -------------------

10x - 2y = 18

10x/10 = 18 + 2y/10

x = 9/5 + y/5

Solve for y:

7(9/5 + y/5) + 2y = -1

63/5 + 7y/5 + 2y - 1

63/5 + 7y/5 = 10y/5 = -1

63/5 + 17y/5 = -1 (-5/5)

17y/5 = -68/5 (cancel the 5)

y = -68/17

y = - 4 (Your Answer)

7x + 2(- 4) = -1

7x + (-8) = -1

7x = 7

x =   1

CHECK=

7(1) + 2(-4) = -1

7+ (-8) = -1.

-1=-1

Answer 2

Answer:

(1, -4).

(x = 1, y = -4).

Step-by-step explanation:

7x + 2y = -1

3x  – 4y = 19    Multiply the first equation by 2:

14x + 4y = -2     Adding:

17x = 17

x = 1.

Plug this into the second equation:

3(1) - 4y = 19

-4y =  19 - 3 = 16

y = -4.