Mathematics for IGCSE & O level - Equations (Section 4 - No. 5)
How can you solve 2x + 3y = 7 and x - y = 1 using substitution?
Solve the second equation for x: x = y + 1
Substitute (y+1) for x in the first equation
Solve the first equation for x and substitute
Use 2 equations.
Explicació
Isolate one variable in terms of the other (e.g., solve for x in the second equation) and substitute that expression into the other equation.