Solve the simulaneous Equations: 5x + y = 21, x - 3y = 9

Steps to solve a simultaneous Equation:1) Make x and y coefficients the same2) Subtract or add (of which depends on scenario) equations to eliminate x or y3) Solve remaining variable4) Plug into other equation to find x or y(1) 5x+y=21(2) x-3y=9 ---------- (Multiply (2) by 5)5x + y = 215x - 15y = 45----------- (1)-(2)0 +16y = -24, y = -1.5----------- (Plug -1.5 into y in equation (1))5x - 1.5 = 215x = 22.5x = 4.5

TT
Answered by Tait T. Maths tutor

2797 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

How to find the roots of a Quadratic Equation by Factorising?


Prove that the composite function fg(2)=-26 where f(x)=3x+1 and g(x)=1-5x


A straight line passes through the points (-2, 4) and (1, 10). What is (a) the gradient of the line, (b) the y-intercept of the line and (c) the equation of the line?


How do you solve a quadratic equation?


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

MyTutor is part of the IXL family of brands:

© 2025 by IXL Learning