Solve the following simultaneous equations. 2x + 5y = -4. 7x + y = 19

Simultaneous equations have 2 or more unknowns. This simultaneous equation has 2 unknowns, and 2 equations. This simultaneous equation can be solved using elimination or substitution. Substitution involves substituting a value of one of the unknowns into one equation(for example, x=2) from the equation. Then you can find the other unknown (for example, y). The other way to solve this equation, and for this equation the simpler way, is elimination. This involves eliminating one of the unknowns from the equation. This is done by making the coefficient of the unknown the same in both equations. eq1: 2x + 5y = -4eq2: 7x + y = 19By multiplying eq2 by 5, this makes the coefficients of unknown y the same. eq2(*5): 35x +5y = 95Then we can eliminate the y unknown by subtracting eq1 from eq2(*5).35x + 5y = 95-2x + 5y = -4-----------------(35x - 2x) + (5y - 5y) = (95 - -4)33x = 99 x = 3Once we have found x, we substitute this into one of the original equations (eq1 or eq2). 2(3) + 5y = -46 + 5y = -45y = -4 -6 5y = -10y = -2

AL
Answered by Aisling L. Maths tutor

3497 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

There are 720 boys in a school and 700 girls. The probability that a girl chosen at random studies french is 3/5 and the probability that a boy chosen at random studies french is 2/3. What is the total number of students in the school that study french?


Find the equation of the straight line joining points (-1, -4) and (2, 5)


Find the co-ordinates where the curve y= 2x^2 + 7x + 3 crosses the x axis


How do you convert fractions to decimals? For example. Convert 13/20 to a decimal.


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