Solving Equations with Substitution

The first step in solving using the substitution method is __________.

• get x by itself

• get y by itself

• get either variable by itself

• add the equations together

Which variable should you isolate first in the system?

• The x in the first equation

• The y in the first equation

• The y in the second equation

• The x in the second equation

What is the correct first step in solving this system by substitution?

• -7(2y+11) - 2y = -13

• -7x -2(2y +11) = -13

• 2y+11-2y = -13

Solve the system by substitution

3x - y = 4

x + 2y = 6

• (-2, 2)

• (2, -2)

• (2, 2)

• (-2, -2)

Solve the system of equations using substitution:

-4x + 4y = 8

y = -2x - 10

• (-4, -2)

• (12, -34)

• (4, -18)

• (-2, -6)

Solve the simultaneous equations by substitution

x+y=5

x-y=1

• x=2, y=3

• x=3, y=2

• x=3, y=-2

• x=-3, y=2

Solve the system by substitution:
y = x + 5
4x + y = 20

• (3,8)

• (8,3)

• (0,2)

• (2,0)

Using the simultaneous equations 2x+10y=60 and -45 + 30y = 21x, find the solution, giving your answer as a coordinate pair

• (6, 5)

• (5, 5)

• (5, 6)

• (5, 5)

What is the first step in solving a system by Substitution?

• Make sure both equations are in standard form.

• Make sure at least one equation is solved for one variable.

• Make sure both equations are in slope-intercept form.

• Make sure both equations can be solved.

Christian had brochures printed for a new business venture. Christian originally ordered 4 boxes of black-and-white brochures and 3 boxes of colour brochures, which cost a total of $134. After those ran out, Christian spent $120 on 3 boxes of black-and-white brochures and 3 boxes of colour brochures. Which system represents this situation?

• x+y=134
  x+y=120

• 3x+3y=134
  4x+3y=120

• 4x+3y=134
  3x+3y=120

• 7xy=134
  6xy=120