1. Algebra 1 Section 7.3 Solve linear systems by linear combinations
a – b = 8
a + b = 20
Solve
3x – 2y = 1
2x + 2y = 4

2. Solve by linear combinations
x – y = -5 x + 2y = 4
To solve by linear combinations
Make the coefficients on one of the variable terms opposites
Add the equations to eliminate one variable term
Solve the equation
Substitute and solve for the other variable

3. solve
2a + 6b = 4 3a – 7b = 6
10x + 16y = 140 5x – 8y = 60

4. solve
x + 1 – 3y = 0 2x = 7 – 3y

5. Page 413 ex 4 x = gold volume y = silver volume Gold + silver = total
volume volume volume
Gold Gold Silver . Silver = Weight
Density Volume Density Volume

6. assignment
Page 414 Problems 8 – 42 even,43,44,58