Could someone please help me with this?
For the following system, if you isolated y in the second equation to use the Substitution Method, what expression would you substitute into the first equation?

5x + 3y = 9
12x + 3y = 18

Question

Could someone please help me with this?
For the following system, if you isolated y in the second equation to use the Substitution Method, what expression would you substitute into the first equation?

 5x + 3y = 9
12x + 3y = 18

jim_thompson5910 · Answer

If you isolate y in the second equation, then...


12x + 3y = 18

3y = 18-12x

3y = -12x+18

y = -12x/3 + 18/3

y = -4x + 6


So you would substitute the expression -4x+6 in for 'y' in the first equation to go from


5x+3y = 9

to

5x+3(-4x+6) = 9

jim_thompson5910 · Answer

From there, you can solve for x and then use that solution to find y.