Search our library of Maths GCSE questions

Top answers

Maths

GCSE

Solve the equation x^2-10x+21=0

First of all notice the highest power on this equation is '2' so it must be a quadratic equation. Using the general form Ax^2+Bx+C=0 we must find two numbers that are factors of C and add together to get ...

Answered by Simran S. • Maths tutor

4417 Views

A box contains an assortment of 100 coloured marbles, coloured red, blue and green. The ratio of blue balls to green balls is 1:3. If there are 16 red balls in the box, what is the ratio of red balls to green balls, and red balls to blue balls?

The student should state that there are x blue balls. From this, they may determine that overall, the number of blue and green balls combined must be 4x, and hence the number of red balls is therefore '10...

Answered by Daniel H. • Maths tutor

2338 Views

Make x the subject of the following formula: 5(3x -2y) = 14 - 2ax

(1) 5(3x - 2y) = 14 -2ax 15x - 10y = 14 - 2ax (2) 15x +2ax -10y = 14 15x + 2ax = 10y + 14
(3) x(15 + 2a) = 10y + 14 x = (10y + 14) / (15 + 2a)
To asking us to make x the subject of a fo...

Answered by Thomas W. • Maths tutor

3117 Views

A is the point (2,-5), B is the point (-1,4). (a) What is the gradient of the line passing through points A and B? (b) Does the point (-100,301) lie on the line passing through points A and B?

(a) let A be (x1,y1) and B be (x2,y2), Gradient = m = (y2-y1)/(x2-x1) m = (4- -5)/(-1-2) = 9/(-3) = -3 Gradient = -3
(b) equation of a straight line line: y = mx + c => y1 = ...

Answered by Hallam M. • Maths tutor

2832 Views

Factorise: x^2+2x-3

think of it in the form of Ax^2 +Bx +C. Most of the GCSE examples will have A as zero so we will ignore the A. To factorise this you need to find what two numbers multiply to make C and adds to make B. In...

Answered by Katherine A. • Maths tutor

2846 Views