Solve the Equation: Use Substitution for 8x - 2y = 10 and 3x + 3y = 9

Question

Find the value of x and and band the substitution method.

{8x2y=103x+3y=9 \begin{cases} 8x-2y=10 \\ 3x+3y=9 \end{cases}

Video Solution

Step-by-Step Solution

To solve this system of equations using the substitution method, follow these steps:

  • Solve 3x+3y=9 3x + 3y = 9 for y y :

Divide the whole equation by 3 to simplify:
x+y=3 x + y = 3

  • Express y y in terms of x x :

y=3x y = 3 - x

  • Substitute y=3x y = 3 - x into the first equation:

We substitute into 8x2y=10 8x - 2y = 10 :
8x2(3x)=10 8x - 2(3 - x) = 10

Simplify and solve for x x :

8x6+2x=10 8x - 6 + 2x = 10
10x6=10 10x - 6 = 10
Add 6 to both sides:
10x=16 10x = 16
Divide by 10:
x=1610=85 x = \frac{16}{10} = \frac{8}{5}

  • Substitute back to find y y :

Use y=3x y = 3 - x :
y=385=15585=75 y = 3 - \frac{8}{5} = \frac{15}{5} - \frac{8}{5} = \frac{7}{5}

Therefore, the solution to the system is x=85 x = \frac{8}{5} and y=75 y = \frac{7}{5} .

Answer

x=85,y=1410 x=\frac{8}{5},y=\frac{14}{10}