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Solving Equations Using Substitution Practice
Complete this assessment to review what you've learned. It will not count toward your grade.
4 of 54 of 5 Items

Question
Solve the system of equations.
–9x+y=12

2x+4y= −28
(1 point)
(
,
)

1 answer

To solve the system of equations given by:

  1. \( -9x + y = 12 \) (Equation 1)
  2. \( 2x + 4y = -28 \) (Equation 2)

we can use substitution or elimination. Let's use substitution for this example.

Step 1: Solve Equation 1 for \( y \)

From Equation 1: \[ y = 9x + 12 \]

Step 2: Substitute \( y \) from Equation 1 into Equation 2

Substituting \( y \) into Equation 2: \[ 2x + 4(9x + 12) = -28 \]

Step 3: Simplify the equation

Expanding the equation: \[ 2x + 36x + 48 = -28 \] \[ 38x + 48 = -28 \]

Step 4: Solve for \( x \)

Subtract 48 from both sides: \[ 38x = -28 - 48 \] \[ 38x = -76 \] \[ x = -\frac{76}{38} = -2 \]

Step 5: Substitute \( x \) back into the equation for \( y \)

Using \( x = -2 \) in \( y = 9x + 12 \): \[ y = 9(-2) + 12 \] \[ y = -18 + 12 \] \[ y = -6 \]

Final Answer:

The solution to the system of equations is: \[ (x, y) = (-2, -6) \]

So, the answer is \((-2, -6)\).