What is the value of y in this system of equations? Negative 6 x + 2 y = negative 18. Negative 3 x minus 2 y = 54.

Question

I NEED HELP!!!!

Answer 1

-6x + 2y = -18 This one calls out to be done with elimination of the "y" terms! Add the two equations.

-3x - 2y = 54

-9x = 36

x = -4

-3(-4) - 2y = 54 Substitute x = 4 into 2nd equation to find y (could also use 1st eqn, but check both).

12 - 2y = 54

-2y = 42

y = -21

See Desmos Graphing Calculator website to plot both eqns and find intersection.

Answer 2

-6x +2y =-18

divide by 2

-3x +y =-9

y = 3x-9

-3x -2y = 54

2y = -3x-54

-18+6x =-3x -54

9x = -54+18= -36

divide by 9

x = -36/9 = -4

x=-4

y = 3(-4)-9= -12-9= -21

x=-4 and y =-21

check the answer

plug those x and y values into the 2 original equations

-6x +2y = -18

-6(-4) +2(-21)

=24-42

= -18

-3x -2y = 54

-3(-4) -2(-21)

=12 +42

=54

they work, they satisfy both original equations

solve the system by substitution, elimination or linear algebra