Math 1 U4 L4: Systems-Substitution

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

• get x by itself

• get y by itself

• get either variable by itself in one equation

• add the equations together

y = -6
-3x - 6y = 24

• (6, 6)

• (6, -6)

• (4, -6)

• (-6, 4)

What is the solution to the system of equations? What is the value of y in the solution to this system?

y = 3x - 8

y = 4 - x

Solve:
x = -3y - 17
2x + 3y = -7

• (1, -20)

• (3, 0)

• (-5, -2)

• (10 , -9)

Solve the system of equations using substitution:
-4x + 4y = 8
y = -2x - 10

• (-4, -2)

• (12, -34)

• (4, -18)

• (-2, -6)

Solve using Elimination method.

-3x - 9y = 15

x +3y = - 5

• Infinitely Many Solutions

• No Solution

• (0,0)

• (15,0)

• (3,9)

Solve the system:
x + 6y = 17
x - 3y = 8

• (5, 2)

• (11, 1)

• (1, 11)

• no solution

What is the solution?

3x + 5y = 13

2x + y = 4

• Infinite solutions

• (2,1)

• (1,2)

• No solution

Solve the following system by substitution method

4x - 5y = 21

x - 3y = 7

What is the sum of the x & y values of the solution?

The solution (x, y) to a system of equations is the point where they...? 

• Run off the graph

• Don't touch

• Intersect

• Exist