Question

How do I do substitution method on the problem
3x-4y=10
2y=2x-6

Answer 1

can you solve the 2nd one for "y"? what do you get?

Answer 2

I know I have to get y by its self right?

Answer 3

yes

Answer 4

ok so ...let me try it

Answer 5

um if i subtract -2y its going to cancel the y out on the equal sign

Answer 6

yes, so you instead divide by 2 both sides

Answer 7

\(\bf \cfrac{2y}{2}=\cfrac{2x-6}{2}\)

Answer 8

whoa ok that was smart lol

Answer 9

ok so 3x-4y=10 and y=2x-6

Answer 10

now I do 3x-4(2x-6) = 10

Answer 11

well... more like .. one sec

Answer 12

\(\bf \begin{array}{llll}
3x-4{\color{red}{ y}}=10\\
2y=2x-6\implies {\color{red}{ y}}=\cfrac{2x-6}{2}\implies\bf {\color{red}{ y}}=x-3
\end{array}\quad thus\\ \quad \\
3x-4{\color{red}{ y}}=10\implies 3x-4({\color{red}{ x-3}})=10\)

Answer 13

you have to substitute the 2y=2x-6 into the 3x. Like this 3(2y=2x-6)-4y=10.

Answer 14

ohh i forgot the fraction part..thank you I see it nowww

Answer 15

yw

Answer 16

why do you have to divide 2x-6?