Solve simultaneously: x^2+y^2=25 and y-3x=13

The substitution method means we have to rearrange the linear equation to find a variable, either x or y, then substitute it into the quadratic (and more difficult to solve) equation, as follows...x2+y2=25 y=3x+13x2+(3x+13)2=25x2+9x2+78x+169=2510x2+78x+144=05x2+39x+72Factorise...(5x+24)(x+3)=0x=-24/5, x=-3Sub in linear equation for y...when x=-24/5, y=-7/5when x=-3, y=4

SC
Answered by Saffron C. Maths tutor

2924 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

if x^2 + 9x + 20 = 0, what are the possible values of x?


y = x^2 + 4x + 7 Find the turning point of the equation by completing the square.


If 4x + 3y = 4 and x + 2y = 2 what are the values of x and y ?


How do I simplify surds?


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