 # Use Substitution to solve a + s = 304 and 7a + 2s = 1118

<-- Equation 1
<-- Equation 2

## Use the substitution method to solve:

a + s = 304
7a + 2s = 1118

Equation 1 is in the correct format.
Equation 2 is in the correct format.

7a + 2s = 1118

## Subtract 2s from both sides to isolate a:

7a + 2s - 2s = 1118 - 2s
7a = 1118 - 2s

## Now divide by 7:

 7a 7
 =
 1118 - 2s 7

## Revised Equation 2:

 a  = 1118 - 2s 7

## Plug Revised Equation 2 value into a:

1(a) + s = 304
1 * ((1118 - 2s)/7) + s = 304
((1118 - 2s)/7) + s = 304

## Multiply equation 1 through by 7

7 * (((1118 - 2s)/7) + s = 304)
7 * (((1118 - 2s)/7) + s = 304)
1118 - 2s + 7s = 2128

## Group like terms:

-2s + 7s = 2128 - 1118
5s = 1010

## Divide each side by 5

 5s 5
 =
 1010 5

 s  = 1010 5

s = 202

## Plug this answer into Equation 1

1a + 1(202) = 304
1a + 202 = 304
1a = 304 - 202
1a = 102

## Divide each side by 1

 1a 1
 =
 102 1

 a  = 102 1

a = 102

Solve using Gauss Jordan Elimination

a = 102 and s = 202

### 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.

### What 1 formula is used for the Simultaneous Equations Calculator?

1. Δ = a * e - b * d

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### 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