Question

a student claims that the best way to solve the system at the right is by substitution.Do you agree? explain system:y-3x=4 y-6x=12

Answer 1

in stuck on this question

Answer 2

Either of the given equations is very easily solved for y. What does that tell you?

Answer 3

umm....that it can be substitution?

Answer 4

yes....you can easily solve one of the equations for y, then sub that back into the other equation. Do you need me to show you ?

Answer 5

YES! plz it would be a big help. @texaschic101

Answer 6

y - 3x = 4......solve for y by adding 3x to both sides
y = 3x + 4
now sub 3x + 4 in for y in the other equation to find x

y - 6x = 12
(3x + 4) - 6x = 12
3x - 6x = 12 - 4
-3x = 8
x = -8/3

now you would sub -8/3 in for y in either of the original equations
y - 3x = 4
y - 3(-8/3) = 4
y + 24/3 = 4
y = -24/3 + 4
y = -24/3 + 12/3
y = -12/3
y = -4