Solve these simultaneous equations: 3xy = 1, and y = 12x + 3

From first equation: 3xy = 1 => x = 1/(3y)Substitute expression for x into second equation: y = 12x + 3 => y = 12(1/3y) + 3 = 4/y +3Multiply through by y: y2 = 4 + 3y => y2 - 3y - 4 = 0Factorise: (y-4)(y+1) = 0 => y = 4, y = -1 are solutionsx = 1/3y = 1/12, -1/3
Solutions are (1/12,4) and (-1/3, -1)

HM

Related Further Mathematics GCSE answers

All answers ▸

(x+4)((x^2) - kx - 5) is expanded and simplified. The coefficient of the x^2 term twice the coefficient of the x term. Work out the value of k.


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.


How do I know I can multiply two matrices and if so, how do I do it?


The equation of a curve is y = x^2 - 5x. Work out dy/dx