Simultaneous equations 1

## Simultaneous equations

Simultaneous equations have two unknowns

You need to find the values for the two unknowns which make both equations true

## Algebraic solution

Number each equation

If necessary, multiply the equations so that the coefficients of one unknown are the same

Add or subtract the equations to eliminate that unknown

Once one unknown is found use substitution to find the other

Check the answer by substituting both values into the other equation

## Easier eliminations

You can save time by choosing the right unknown to eliminate

Look for one of these

If an unknown appears on its own in one equation you only need to multiply one equation to eliminate that unknown

If an unknown has different signs in the two equations tou can eliminate by adding

## Check it

Always use the equation you didn’t substitute into to check your answer

Graphical solution

You can solve these simultaneous equations by drawing a graph

The coordinates of the point of intersection give the solution to the simultaneous equation

# Simultaneous equations 1

## Simultaneous equations

Simultaneous equations have two unknowns

You need to find the values for the two unknowns which make both equations true

## Algebraic solution

Number each equation

If necessary, multiply the equations so that the coefficients of one unknown are the same

Add or subtract the equations to eliminate that unknown

Once one unknown is found use substitution to find the other

Check the answer by substituting both values into the other equation

## Easier eliminations

You can save time by choosing the right unknown to eliminate

Look for one of these

If an unknown appears on its own in one equation you only need to multiply one equation to eliminate that unknown

If an unknown has different signs in the two equations tou can eliminate by adding

## Check it

Always use the equation you didn’t substitute into to check your answer

Graphical solution

You can solve these simultaneous equations by drawing a graph

The coordinates of the point of intersection give the solution to the simultaneous equation