Use the substitution method to solve:
12f + 8i = 260
15f + 6i = 240
Check Format
Equation 1 is in the correct format.
Check Format
Equation 2 is in the correct format.
Rearrange Equation 2 to solve for f:
15f + 6i = 240
Subtract 6i from both sides to isolate f:
15f + 6i - 6i = 240 - 6i
15f = 240 - 6i
Now divide by 15:
| 15f | |
| 15 |
| = |
| 240 - 6i |
| 15 |
Revised Equation 2:
| f = | 240 - 6i |
| 15 |
Plug Revised Equation 2 value into f:
12(f) + 8i = 260
12 * ((240 - 6i)/15) + 8i = 260
((2880 - 72i)/15) + 8i = 260
Multiply equation 1 through by 15
15 * (((2880 - 72i)/15) + 8i = 260)
15 * (((2880 - 72i)/15) + 8i = 260)
2880 - 72i + 120i = 3900
Group like terms:
-72i + 120i = 3900 - 2880
48i = 1020
Divide each side by 48
| 48i | |
| 48 |
| = |
| 1020 |
| 48 |
| i = | 1020 |
| 48 |
i = 21.25
Plug this answer into Equation 1
12f + 8(21.25) = 260
12f + 170 = 260
12f = 260 - 170
12f = 90
Divide each side by 12
| 12f | |
| 12 |
| = |
| 90 |
| 12 |
| f = | 90 |
| 12 |
f = 7.5
Test Your Knowledge?
- What are the 3 methods to solve a system of 2 equations?
- With the elimination method, what are you trying to eliminate?
Common Core State Standards In This Lesson
CCSS.MATH.CONTENT.8.EE.C.8,CCSS.MATH.CONTENT.8.EE.C.8.B
What is the Answer?
f = 7.5 and i = 21.25
How does the Simultaneous Equations Calculator work?
Free Simultaneous Equations Calculator - Solves a system of simultaneous equations with 2 unknowns using the following 3 methods:
1) Substitution Method (Direct Substitution)
2) Elimination Method
3) Cramers Method or Cramers Rule Pick any 3 of the methods to solve the systems of equations 2 equations 2 unknowns
This calculator has 2 inputs.
1) Substitution Method (Direct Substitution)
2) Elimination Method
3) Cramers Method or Cramers Rule Pick any 3 of the methods to solve the systems of equations 2 equations 2 unknowns
This calculator has 2 inputs.
What 1 formula is used for the Simultaneous Equations Calculator?
Δ = a * e - b * d
What 7 concepts are covered in the Simultaneous Equations Calculator?
- cramers rule
- an explicit formula for the solution of a system of linear equations with as many equations as unknowns
- eliminate
- to remove, to get rid of or put an end to
- equation
- a statement declaring two mathematical expressions are equal
- simultaneous equations
- two or more algebraic equations that share variables
- substitute
- to put in the place of another. To replace one value with another
- unknown
- a number or value we do not know
- variable
- Alphabetic character representing a number
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