# Python – Solve the Linear Equation of Multiple Variable

**Prerequisite: **Sympy.solve()

In this article, we will discuss how to solve a linear equation having more than one variable. For example, suppose we have two variables in the equations. Equations are as follows:

x+y =1

x-y =1

When we solve this equation we get x=1, y=0 as one of the solutions. In Python, we use Eq() method to create an equation from the expression.

Syntax :Eq(expression,RHS value)

For example, if we have expression as x+y = 1. It can be written as Eq(x+y,1)

### Solving equation with two variables

Construct the equations using Eq() method. To solve the equations pass them as a parameter to the **solve()** function.

**Example :**

## Python3

`# importing library sympy ` `from` `sympy ` `import` `symbols, Eq, solve ` ` ` `# defining symbols used in equations ` `# or unknown variables ` `x, y ` `=` `symbols(` `'x,y'` `) ` ` ` `# defining equations ` `eq1 ` `=` `Eq((x` `+` `y), ` `1` `) ` `print` `(` `"Equation 1:"` `) ` `print` `(eq1) ` `eq2 ` `=` `Eq((x` `-` `y), ` `1` `) ` `print` `(` `"Equation 2"` `) ` `print` `(eq2) ` ` ` `# solving the equation ` `print` `(` `"Values of 2 unknown variable are as follows:"` `) ` ` ` `print` `(solve((eq1, eq2), (x, y))) ` |

**Output:**

Equation 1: Eq(x + y, 1) Equation 2 Eq(x - y, 1) Values of 2 unknown variable are as follows: {x: 1, y: 0}

### Solving equation with three variables

Construct the following equations using Eq() and solve then to find the unknown variables.

x +y+z =1

x+y+2z=1

**Example: **

## Python3

`# importing library sympy ` `from` `sympy ` `import` `symbols, Eq, solve ` ` ` `# defining symbols used in equations ` `# or unknown variables ` `x, y, z ` `=` `symbols(` `'x,y,z'` `) ` ` ` `# defining equations ` `eq1 ` `=` `Eq((x` `+` `y` `+` `z), ` `1` `) ` `print` `(` `"Equation 1:"` `) ` `print` `(eq1) ` ` ` `eq2 ` `=` `Eq((x` `-` `y` `+` `2` `*` `z), ` `1` `) ` `print` `(` `"Equation 2"` `) ` `print` `(eq2) ` ` ` `eq3 ` `=` `Eq((` `2` `*` `x` `-` `y` `+` `2` `*` `z), ` `1` `) ` `print` `(` `"Equation 3"` `) ` ` ` `# solving the equation and printing the ` `# value of unknown variables ` `print` `(` `"Values of 3 unknown variable are as follows:"` `) ` `print` `(solve((eq1, eq2, eq3), (x, y, z))) ` |

**Output:**

Equation 1: Eq(x + y + z, 1) Equation 2 Eq(x - y + 2*z, 1) Equation 3 Values of 3 unknown variable are as follows: {x: 0, y: 1/3, z: 2/3}

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