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Maths
GCSE

How do I use completion of the square to solve a quadratic function?

I'll use an example to illustrate this:"find the roots of x2+6x-15"The advantage of completing the square for a quadratic is that it also gives the turning point of the parabola.Here,...

Answered by Laure-Anne H. Maths tutor
2627 Views

There are 10 boys and 20 girls in a class. The mean mark in a test for all the class is 60. The mean mark for the girls is 54. Work out the mean mark for the boys.

First let us consider how we calculate the mean test mark in the first place, we add up the individual test marks of the entire class to give the total test mark then we divide by the number of students. ...

Answered by Adam D. Maths tutor
60484 Views

A GCSE is graded out of 140 marks. 1/5 of these marks were given for coursework. The rest were divided between two reading and listening tests, with the marks split in the ratio 3:4 respectively. How many marks were given for the reading test?

140/5 = 28140 - 28 = 1123 + 4 = 7112/7 = 1616 x 3 = 48Answer: 48 (Would go through methods with student: order of thinking, dealing with ratio, long division)

Answered by Will B. Maths tutor
3357 Views

The equation 5x^2 + px + q = 0, where p and q are constants, has roots t and t+4. Show that p^2 = 20q + 400.

We know that if we have a polinomial of the form ax^2 + bx + c = 0, then:sum of the roots = -b/a and product of the roots = c/a Therefore: t + (t + 4) = -p/5 and t(t + 4) = q/5 Therefore: 2t + 4 = -p...

Answered by Alexandra B. Maths tutor
3948 Views

Solve the simultaneous equations: 3x+5y=19, 4x-2y=-18

For all simultaneous equations it is useful to number each one to keep your working clear and concise. In order to solve this we need to eliminate one of the variables (x or y) by manipulating the equatio...

Answered by Ben W. Maths tutor
7845 Views

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