Differential equations are equations that contain derivatives. The equations are used in calculus to describe relationships among one or more variables. A solution to any series of equations can be ...

Simultaneous equations like 𝒚 = 2𝒙 - 1 and 𝒚 = 𝒙 + 1 can be represented graphically. To solve the equations graphically, the two lines 𝒚 = 𝒙 + 1 and 𝒚 = 2𝒙 - 1 are drawn on the same diagram.

Be careful to note what a GCSE question is asking. If it states ‘solve algebraically’ then you must do so. To find solutions from graphs, look for the point where the two graphs cross one another.