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By factorising, solve the quadratic equation x^2-8x+15=0

First we find two numbers that that add up to -8 and multiply to make 15. In this case the numbers are -3 and -5. This means we can now factorise the quadratic to give (x - 5) (x - 3) = 0. For the above to b...
IN
Answered by Ivo N. • Maths tutor
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How do you use the completing the square method to solve a quadratic equation?

First you need to get the quadratic equation in completed square form. This looks like: (x+p)^2 + q To put an expression in completed square form you can use this formula: x^2 + 2bx + c = (x+b)^2 - b^2 + c O...
CP
Answered by Caroline P. • Maths tutor
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Solve 5x - 2 > 3x + 11

When solving inequalities the first step is to put the unknown, in this case x, on the same side of the inequality sign. Remember when you move values to the other side of a sign they change their charge as ...
SR
Answered by Sarina R. • Maths tutor
6360 Views

The time, T seconds, it takes a water heater to boil a constant mass of water is inversely proportional to the power, P watts, of the water heater. When P is 300, T is 20. What is T when P is 400?

This is a question regarding inverse proportion. This is when one value increases as the other decreases. For this question, the equation can be written as: T ∝ 1/P The directly proportional sign (∝) can be ...
SA
Answered by Scott A. • Maths tutor
12443 Views

Find the area of a sector with a radius of 5cm and an angle of 120 degrees?

pi r r pi 5x5 25pi = 360 degrees 120/360 x 25pi = 25/3 pi Teaching Points: Area of a circle + other formalue for circumfrence Degrees of a circle Fractions Dealing with Pi Terminology of sector + cord + tang...
AP
Answered by Anish P. • Maths tutor
5469 Views