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.

Journal of Applied Econometrics, Vol. 10, No. 2 (Apr. - Jun., 1995), pp. 187-200 (14 pages) We propose a general strategy to estimate semi-parametrically simultaneous equations with limited dependent ...

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.