Solve the System: Equations 6x + 4y = 18 and -2x + 3y = 20

Question

6x+4y=18 6x+4y=18

2x+3y=20 -2x+3y=20

Video Solution

Step-by-Step Solution

To solve this problem, we'll use the elimination method:

  • Step 1: Align the coefficients of x x to eliminate it.
  • Step 2: Subtract one equation from the other to solve for the remaining variable.
  • Step 3: Substitute the known variable back into one of the original equations to find the value of the second variable.

Now, let's work through each step:

Step 1: The given system of equations is:

6x+4y=18 6x + 4y = 18 (Equation 1)

2x+3y=20 -2x + 3y = 20 (Equation 2)

To eliminate x x , we want the coefficients of x x to be equal in magnitude. Multiply Equation 2 by 3 to match the x x coefficient in Equation 1:

3(2x+3y)=3(20) 3(-2x + 3y) = 3(20)

This results in:

6x+9y=60-6x + 9y = 60 (Equation 3)

Step 2: Add Equation 1 and Equation 3 to eliminate x x :

(6x+4y)+(6x+9y)=18+60 (6x + 4y) + (-6x + 9y) = 18 + 60

This simplifies to:

13y=78 13y = 78

Solving for y y , we divide both sides by 13:

y=7813=6 y = \frac{78}{13} = 6

Step 3: Substitute y=6 y = 6 back into Equation 1:

6x+4(6)=18 6x + 4(6) = 18

6x+24=18 6x + 24 = 18

Subtract 24 from both sides:

6x=1824 6x = 18 - 24

6x=6 6x = -6

Divide both sides by 6:

x=66=1 x = \frac{-6}{6} = -1

Therefore, the solution to the system of equations is x=1,y=6\mathbf{x = -1, y = 6}.

Answer

x=1,y=6 x=-1,y=6