Question

Cómo hallar el valor de variables

Answer 1

`7y+3x=9`

Variables are the unknows, on this case we have 2 variables

Y and X

variables are always represented by letters

X is

we write the original equation

`7y+3x=9`

now we try to x be alone to solve, then we subtract 7y on both sides

`\begin{gathered} (7y-7y)+3x=9-7y \\ 0+3x=9-7y \\ 3x=9-7y \end{gathered}`

now we divide on both sides by 3 to solve x

`\begin{gathered} (3x)/(3)=(9-7y)/(3) \\ \\ x=(9-7y)/(3) \end{gathered}`

Y is

write original equation

`7y+3x=9`

subtract 3x on both sides to remove 3x on right

`\begin{gathered} 7y+(3x-3x)=9-3x \\ 7y+0=9-3x \\ 7y=9-3x \end{gathered}`

and divide by 7 to solve y

`\begin{gathered} (7y)/(7)=(9-3x)/(7) \\ \\ x=(9-3x)/(7) \end{gathered}`