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There are n sweets in a bag, 6 of which are orange. If the probablility of eating 2 orange sweets from the bag, one after the other, is 1/3, show that n^2 - n - 90 = 0. State any assumptions made.

We are assuming that the sweets are selected at random. The question says that the sweets are eaten, so we are also assuming that they aren't put back into the bag. The total probability of selecting the two...
JB
Answered by James B. • Maths tutor
4466 Views

Give an example of a real-world system that would be described by a quadratic equation. Explain the significance of the two real roots, a repeated root, and undefined roots. Is there any significance to a positive or a negative answer in your example?

For a ball that has been thrown, it's height above the ground can be described by a quadratic equation of the time since it was thrown and gives a parabola. The two real roots of the equation are the times w...
JB
Answered by James B. • Maths tutor
4692 Views

How can i use completing the square to factorise and solve equations

This method will only work if your x term is divisible by 2. For example x 2 + 6x + 12. You then use the halved x term (e.g. 3x) to complete the square. The beginning of your factorisation is now (x + 3) 2 ....
NS
Answered by Natalie S. • Maths tutor
5022 Views

Draw y + 14 = x ( x - 4 ) and label all points of intersection with axes.

To begin with, lets rewrite the equation in a way which is easier to understand by making y the subject and multiplying out the brackets: y = x 2 - 4x - 14 this looks significantly easier to understand and i...
TF
Answered by Thomas F. • Maths tutor
3910 Views

Differentiate: sin(x) + 2x^2

To tackle this problem, we will spilt the two terms given. Firsly, we'll take the sin(x) by itself: d/dx (sinx) = cos(x) - where d/dx means the differential of what is inside the bracket. This is a key diffe...
EL
Answered by Emma L. • Maths tutor
4479 Views