Simultaneous Equation: 3x + y = -4 / 3x - 4y = 6

Route 1 (Standard): 1. 3x + y = -4 / 2. 3x - 4y = 6 / MINUS 2 FROM 1 / y - (-4y) = 5y / -4 - 6 = - 10 / 5y = - 10 / y = -2 /PUT y-VALUE BACK INTO ORIGINAL EQ  / 3x - 2 = -4 / 3x = - 4 + 2 / 3x = -2 /x = - 2/3 Route 2 (Alternative): 1. 3x + y = -4 GOES TO y = -4 - 3x / 2. 3x - 4y = 6 GOES TO 3x = 6 + 4y / PUT 1 INTO 2/ 3x = 6 + 4(-4 -3x) / 3x = 6 -16 -12x / 3x + 12x = 6-16 / 15x = -10  / x = - 10/15 / x = - 2/3     / PUT x-VALUE BACK INTO 'y' EQ / y = -4 - (3*- 2/3) / y = -4 - (-2) / y = -4 + 2 / y = -2

Related Maths GCSE answers

All answers ▸

There are 720 boys and 700 girls in a school. The probability that a boy chosen at random studies French is 2/3 The probability that a girl chosen at random studies French is 3/5. Work out the number of students in the school who study French.


Factorise x^2 - 7x + 12 = 0


Find the equation of the line passing through the point ( 2, −3) which is parallel to the line with equation y + 4x = 7


Work out: 3 ½ – 2 ⅓ Give your answer as a improper fraction


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo
Cookie Preferences