Question

7x+3y=22 4y=20 I need to know how to write this equation out with the answer

Answer 1

$\begin{cases} 7x+3y=22 \\ 4y=20 \ \ /:4 \end{cases}\\ \\\begin{cases} 7x+3 \cdot 5=22 \\ y= 5 \end{cases}\\ \\\begin{cases} 7x+15=22 \ \ |-15 \\ 4y=20 \end{cases}$

$\begin{cases} 7x+15 -15=22 -15 \\ y=5 \end{cases}\\ \\\begin{cases} 7x =7\ \ / :7 \\ y=5 \end{cases}\\ \\\begin{cases} x =1 \\ y=5 \end{cases}$

Answer 2

7x+3y=22
4y=20

4y=20
y=5

Substitute to first equation
7x+15=22
7x=7
x=1