Question

if u add the two equations 6x+4y=46 and -6x+9y=6 what do you get?

Answer 1

$\begin{gathered} 6x+4y=46 \\ -6x+9y=6 \\ \Rightarrow0\cdot x+13y=52 \\ 13y=52 \\ y=\frac{52}{13} \\ y=4 \end{gathered}$

Combining like terms

$\begin{gathered} 6x+4y-6x+9y=46+6 \\ 6x-6x+4y+9y=46+6 \\ (6-6)x+(4+9)y=52 \\ 0\cdot x+13y=52 \\ 13y=52 \\ y=\frac{52}{13}=4 \end{gathered}$

Think of y = 4 as y=f(x)=4

This means that for any value of x you replace, you will always get y = 4