Substitution

Japanese school year: Junior high 2

What you learn

You will learn how to solve simultaneous equations by isolating one variable in an equation and substituting it into the other. This method is particularly convenient when a variable is already expressed in terms of another. Prior knowledge of rearranging formulas and basic linear equations will support your learning.

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Key points

This form is used when rewriting one equation as $y = \dots$ or $x = \dots$ in the substitution method. Choosing a variable with a coefficient of 1 or -1 makes rearrangement simple without fractions.

y = ax + b

Substitute the rearranged expression, enclosed in parentheses, into the corresponding variable in the other equation. With only one variable remaining, it can be solved as a standard linear equation.

Substitute the value you just found back into the initial " $y = \dots$ " expression to calculate the other variable directly.

Choose a set to practice.

Practice 1Coming soon