What are simultaneous linear equations?

• When you have more than one equation in more than one unknown, then you are dealing with?simultaneous equations
• An equation is?linear?if none of the unknowns in it is raised to a power other than one
• Solving a?pair of simultaneous equations?means finding?pairs of values?that make?both equations true?at the same time
• A linear equation in two unknowns will produce a straight line if you graph it... linear = line
• A pair of simultaneous equations will produce lines that will cross each other (if there is a solution!)

How do I use substitution to solve simultaneous linear equations?

Step 1:?Rearrange one of the equations to make one of the unknowns the subject (if one of the equations is already in this form you can skip to Step 2)

Step 2:?Substitute the expression found in Step 1 into the equation not used in Step 1

Step 3:?Solve the new equation from Step 2 to find the value of one of the unknowns

Step 4:?Substitute the value from Step 3 into the rearranged equation from Step 1 to find the value of the other unknown

Step 5:?Check?your solution by substituting the values for the two unknowns into the original equation you?didn't?rearrange in Step 1