Presentation is loading. Please wait.

Presentation is loading. Please wait.

Solving a system of equations by SUBSTITUTION Step 1: Solve an equation for one variable. Step 2: Substitute Step 3: Solve the equation. Step 4: Plug back.

Similar presentations


Presentation on theme: "Solving a system of equations by SUBSTITUTION Step 1: Solve an equation for one variable. Step 2: Substitute Step 3: Solve the equation. Step 4: Plug back."— Presentation transcript:

1 Solving a system of equations by SUBSTITUTION Step 1: Solve an equation for one variable. Step 2: Substitute Step 3: Solve the equation. Step 4: Plug back in to find the other variable. Step 5: Check your solution. Pick the easier equation. The goal is to get y= ; x= ; a= ; etc. Put the equation solved in Step 1 into the other equation. Get the variable by itself. Substitute the value of the variable into the equation. Substitute your ordered pair into BOTH equations.

2 1) Solve the system using substitution x + y = 5 y = 3 + x Step 1: Solve an equation for one variable. Step 2: Substitute The second equation is already solved for y! x + y = 5 x + (3 + x) = 5 Step 3: Solve the equation. 2x + 3 = 5 2x = 2 x = 1

3 1) Solve the system using substitution x + y = 5 y = 3 + x Step 4: Plug back in to find the other variable. x + y = 5 (1) + y = 5 y = 4 Step 5: Check your solution. (1, 4) (1) + (4) = 5 (4) = 3 + (1) The solution is (1, 4). What do you think the answer would be if you graphed the two equations?

4 Solve the system using substitution 3x – y = 4 x = 4y - 17

5 Solving a system of equations by SUBSTITUTION Step 1:.. Step 2: Step 3: Step 4: Put the equation solved in Step 1 into the other equation Pick the easier equation. The goal is to get y= ; x= ; a he variable by itself. ck the easier equation. The goal is to get y= ; x= ; a= ; etc Pick the easier equation. The goal is to get y= ; x= ; a= ; etc. Using the equation solved in Step 1 replace the variable in the other equation. Therefore you have one equation with one variable. Get the variable by itself. Substitute the value of the variable into the equation. Write your answer as an ordered pair (x, y).

6 REAL WORLD APP You buy a total of 50 burgers and hotdogs for $90. You pay $2 per burger and $1.50 per hotdog. Write a system of equations to find the number of x burgers and y hotdogs.

7 Solve the system by substitution _______burgers and ______hotdogs

8 Try this: You sell lemonade for $2 per cup and orange juice for $3 per cup. You sell a total of 100 cups for $240. Write a system of equations to find the number of x cups of lemonade and y cups of orange juice.

9 Solve the system by substitution _______cups lemonade & ______cups orange juice

10


Download ppt "Solving a system of equations by SUBSTITUTION Step 1: Solve an equation for one variable. Step 2: Substitute Step 3: Solve the equation. Step 4: Plug back."

Similar presentations


Ads by Google