Question

Substitution method...need help.. started but cant finish

Answer 1

Solve either equation for either variable. Since the second one has y on its own, the easiest choice is to solve that for y.

-5x + y = 13   ⇒   y = 5x + 13

Now substitute this into the other equation to eliminate y and rewrite it entirely in terms of x :

-3x + 3y = 3   ⇒   -3x + 3 (5x + 13) = 3

Simplify and solve for x :

-3x + 15x + 39 = 3

12x = -36

x = -3

Substitute this into either original equation to solve for y. Plugging x = -3 into the first equation would give

-3 (-3) + 3y = 3

9 + 3y = 3

3y = -6

y = -2

So the solution to the system of equations is (x, y) = (-3, -2).