Find integers A and B, such that (5x +4)/((2-x)(1+3x)) = A/(2-x) + B/(1+3x)

Adding the fractions on the RHS of the equation in the usual way gives 

A/(2-x) + B/(1+3x) = (A(1+3X) +B(2-X))/((2-X)(1+3X)) = (5x +4)/((2-x)(1+3x)) 

This gives an expression for the original numerator in terms of A B and x. 

A(1+3X) +B(2-X)) = 5x +4

Take values of x which simplify the equation e.g x = 2, -1/3

Gives A = 2, B = 1

So (5x +4)/((2-x)(1+3x)) = 2/(2-x) + 1/(1+3x)

LF

Related Maths A Level answers

All answers ▸

Solve: 2 sin(2x) = (1-sin(x))cos(x) for 0<x<2*Pi and give any values of x, if any, where the equation is not valid


A circle with centre C has equation x^2 + y^2 +8x -12y = 12


A circle has the equation x^2 + y^2 - 4x + 10y - 115 = 0. Express the equation in the form (x - a)^2 + (y - b)^2 = k, and find the centre and radius of the circle.


Find the first differential with respect to x of y=tan(x)