Question

Solve the system of linear equations below, using substitution method.8x +9y = 363x + 4y = 16

Answer 1

Answer:

x = 0, y = 4

Explanations:

The given system of equations is:

8x + 9y = 36............(1)

3x + 4y = 16.............(2)

Make x the subject of the formula from equation (1)

$\begin{gathered} 8x\text{ = 36 - 9y} \\ x\text{ = }\frac{36-9y}{8}\ldots.\ldots\ldots\ldots\ldots\text{.}(3) \end{gathered}$

Substitute equation (3) into equation (2)

$\begin{gathered} 3(\frac{36-9y}{8})\text{ + 4y = 16} \\ \frac{108-27y}{8\text{ }}+4y\text{ = 16} \\ \frac{108-27y+32y}{8}=\text{ 16} \\ \frac{108+5y}{8}=16 \\ 108+5y\text{ = }128 \\ 5y\text{ = 128-108} \\ 5y\text{ = 20} \\ y\text{ = }\frac{20}{5} \\ y\text{ = 4} \end{gathered}$

Substitute the value of x into equation (3)

$\begin{gathered} x\text{ = }\frac{36-9(4)}{8} \\ x\text{ = }\frac{36-36}{8} \\ x\text{ = }\frac{0}{8} \\ x\text{ = 0} \end{gathered}$

The solutions to the system of linear equations are x = 0, y = 4