Question

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

Answer 1

x=0 and y=4
so it is (0,4)

Answer 2

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{ = }(36-9y)/(8)\ldots.\ldots\ldots\ldots\ldots\text{.}(3) \end{gathered}`

Substitute equation (3) into equation (2)

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

Substitute the value of x into equation (3)

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

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