Solving Systems by Substitution

• (-1, -4)

• (-4, -4)

• (4, -4)

• (4, 4)

• (3,-1)

• (-3,1)

• (-3,-1)

• (3,1)

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.

Solve the system by substitution.
 
5x + 4y= −14
y =  −7x  −  15 

• (-2, -1)

• (1, -2)

• (-2, 1)

• (-1, -2)

Solve this system of equations. 
y = 2x + 1
y = 4x - 1

• (1,3)

• (-1,-3)

• (-1,3)

• (3,1)

y = -2x + 5
y = 2x - 11

• No Solution

• (0, 0)

• (3, -1)

• (4, -3)

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

x - 3y = -13
4x + 2y = 4

• (1, 4)

• (-1, -4)

• (-1, 4)

• (1, -4)

y = -3x + 11
5x + y = 21

• (1, -5)

• (1, 5)

• (-4, 5)

• (5, -4)