Question

A variable needs to be eliminated to solve the system of equation below. Choose the correct first step.

3x-9y=-39. 3x-6y=-21

Answer 1

The correct first step to eliminate the variable and solve the system of equations is to subtract the second equation from the first equation. After simplifying, we can divide both sides of the resulting equation to solve for y, which gives the value of y as 6.

Step-by-step explanation:

The correct first step to eliminate the variable and solve the system of equations is to subtract the second equation from the first equation. This can be done by subtracting the left side and right side of the second equation from the respective sides of the first equation.

3x - 9y - (3x - 6y) = -39 - (-21)

After simplifying, we get:

-3y = -18

Divide both sides of the equation by -3 to solve for y:

y = 6

Answer 2

3

−

9

=

−

3

9

3

−

6

=

-21

Step-by-step explanation:

3x​−9y=−39, 3x−6y=−21 : x=5, y=6

Steps

[ ​3x−9y=−39 3x−6y=−21 ]

Show Steps

Isolate x for 3x−9y=−39: x=−13+3y

Substitute x=−13+3y

[ 3(−13+3y)−6y=−21 ]

Show Steps

Simplify

[ −39+3y=−21 ]

Show Steps

Isolate y for −39+3y=−21: y=6

For x=−13+3y

Substitute y=6

x=−13+3· 6

Simplify

x=5

The solutions to the system of equations are: