Question

Y=3x-5
3y-12x=-6
Substitution method

Answer 1

1y = 3x - 5 ⇒ 1y - 3x = - 5 ⇒ 3y + 9x = 15
3y - 12x = -6 ⇒ 3y - 12x = 6 ⇒ 3y - 12x = 6
21x = 21
21 21
x = 1
y - 3(1) = -5
y - 3 = -5
+3 +3
y = 2
(x, y) = (1, 2)

Answer 2

Replace all occurrences of y with the solution found by solving the last equation for y. In this case, the value substituted is 3x−5.
y=3x−5
3(3x−5)−12x=−6

Simplify each term.
y=3x−5
9x−15−12x=−6

Add 9x and −12x to get −3x.
y=3x−5
−3x−15=−6

move -15 to the right-hand side of the equation by adding 15 to both sides.
y=3x−5
−3x=15−6

Subtract 6 from 15 to get 9.
y=3x−5
−3x=9

Simplify

(−3,−14)