The second way to solve systems of equations is by substitution. |
This method is used when you can easily solve for one of the variables, is does not matter which one you solve for. |
The first step is to solve for one of the equations. |
The second step is to put the expression from Step 1into the other equation and solve for the other variable. |
The third step is to plug in the value you solved for in Step 2 into the original equation and solve. |
Solve the system by using the substitution method. 2x+3y=5 x-5y=9 |
|
| Solve the 2nd equation for X. | x=5y+9 |
| Substitute the expression in Step 2 in for x in the second equation. | 2(5y+9)+3y=5 |
| Solve for y. | y=-1 |
| Plug in the -1 for the y. | x-5(-1)=9 or |
| Solve for x. | x=4 |
| Your answer is... | (4,-1) |