Solve the simultaneous equations 4x + 2y =20 and 8x + 6y =45

Let (1) be 4x + 2y =20 and (2) be 8x + 6y =45.First we want to eliminate either x or y so that we have an equation in terms of only one unknown. Lets eliminate x. If we multiply (1) by 2 we have2(4x + 2y) = 2(20) giving 8x + 4y =40. Now the x terms in both equations are the same. Next we subtract 2*(1) from (2) to give:(2) - 2*(1) : (8x + 6y) - (8x + 4y) = 45 - 40 giving 2y = 5. this can be rearranged to find y = 2.5.Finally, the the value for y can be substituted into either (1) or (2) to give the value of x: 4x + 2(2.5) =204x = 15x = 15/4 = 3.75

Answered by Jade R. Maths tutor

2341 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

A game consists of 5 cups turned upside down, under one of the cups is a prize. 5 friend's pick a cup in turn and lifts it up, if they get the prize, they win , but if not, the cup is removed and the next friend picks. What position is it best to pick?


Solve the simultaneous equations 'x-2y=3' and 'x^2+2y^2=27'


How do you factorise?


Write 2x^2 - 16x + 6 in the form a(x + b)^2 + c where a, b and c are constants to be determined.


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