Solve these simultaneous equations.....3a+2b = 17 and 8a-2b= 60

3a+2b = 178a-2b = 60We are going to solve this using the elimination method. This means that we are going to eliminate the variable (or letter) that has the same value in each equation. In this case it is the 'b' because both equations have '2b' in them. Using the SSS abbreviation, which stands for Same Sign Subtract, we can see that the '2b' actually has different signs in the two equations; in the top one it is positive, and in the bottom one it is a negative.With different signs, we therefore have to add the two equations, and this in turn will eliminate the 'b' variable. So if we add 8a+3a we get 11a, and if we get 60 + 17 we get 77. Lining up the variables and the equals sign we get 11a=77. Dividing both sides by 11 gives you a=7. You can then pick either equation to substitute this value back into. Taking the top equation; 3a+2b = 17, we can say 3(7) + 2b =17. Therefore 21 + 2b = 17. Subtracting 21 from both sides gives 2b=-4 and therefore b= -2. Those are your two answers

Answered by Joel O. Maths tutor

4947 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

Solve the following simultaneous equations: 2x-3y=16 x+2y=-6


The ratio 2 centimetres to 6 metres can be written in the form 1 : n. Find the value of n.


Finding the length of the side opposite a known angle while having the hypotenuse length known


3kg of oranges cost £54. 5kg of apples cost £60. Nina buys 2kg of oranges and 7kg of apples. How much does Nina Pay


We're here to help

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

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences