How can I solve simultaneous equations?

There are many options, but substitution is the one we will go through for this example first. Lets say you have 3x+4y = 10 and x+2y = 6In this case substitution would be easiest because you have a singular 'x' in one of the equations. Make x the subject of the second equations so that x = 6 - 2y, and then substitute this into the first equation 3(6 - 2y) + 4y = 10 to give you 18 - 2y = 10. From here simplify to find y: 8 = 2y therefore y = 4. then find x; x = 6 - 2y. x = 6 - 8 therefore x = -2.

TD

Related Maths GCSE answers

All answers ▸

Hairdresser A charges £66 for a haircut and has an offer of 1/3rd off. Hairdresser B charges £70 for a haircut and has an offer of 20% off. Which hairdresser is cheaper?


The equation of the line L1 is y=3x–2. The equation of the line L2 is 3y–9x+5=0. Show that these two lines are parallel.


Factorise x^2+3x-4=0


Solve this set of simultaneous equations: 5x+3=3y 9x+9=6y