 # Do Now 3x – 6y = -3 2x + 4y = 30.

## Presentation on theme: "Do Now 3x – 6y = -3 2x + 4y = 30."— Presentation transcript:

Do Now 3x – 6y = -3 2x + 4y = 30

Homework Solutions 1) x + y = -9 5x + 5y = -45

Homework Solutions 4) 2x + y = 3 -8x – 4y = -12

Homework Solutions 7) 5x + 3y = -10 15x + 9y = -30

Homework Solutions 10) 3x + 2y = -26 12x + 8y = -104

Substitution If x = 5, find the value of 3x.
The substitution property says that a quantity can be substituted for its equal in any expression. We can use this property to solve systems of equations.

Solving Systems Using Substitution
Steps: Find the equation that is solved for a variable. (y = or x = ) Substitute into the OTHER equation. Solve the new equation for the variable. Substitute and solve for the other variable.

Solve using substitution.
y = 3x x + 2y = – 21

Solve using substitution.
y = x – 4 3x + y = 8

x = 4y + 5 x – 3y = – 2

4x + 5y = 11 y = 3x – 13

y = 4x – 1 y = 2x – 5

3x + 2y = -9 x = y – 13

Permission Slips Due Wednesday!!
Homework Worksheet pgs. 68 & 69 #’s 2, 8, 10 Permission Slips Due Wednesday!!

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