Solve these simultaneous equations: 3x-5=-4y and 2xy=-4
First start with 2xy=-4, rearrange to find in terms of x, x=-2/y. Substitute this into the other equation (3x-5=-4y), producing -6/y -5 =-4y.Times every term by -y resulting in 6+5y=4y2 .Rearrange to 4y2-5y-6=0 and solve the quadratic (4y+3)(y-2) = 0 resulting in y=2 or y=-3/4.Substitute into the original equation (2xy=-4) and rearrange for x. x=-2/y. Producing x=-1 or x=8/3
AS
Related Maths GCSE answers
All answers ▸Work out 2 7/15 -1 2/3
There are only 7 blue pens, 4 green pens and 6 red pens in a box. One pen is taken at random from the box. Write down the probability that this pen is blue.
A gym has 275 members. 40% are bronze members. 28% are silver members. The rest are gold members. Work out the number of gold members.
Solve the inequality 3x ≤ 4x+5