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How do I find the roots of a quadratic?

e.g. given x^2 +3x -8 = 0using the quadratic formulayou find x = (-b +- sqrt(b^2 -4ac))/2ayou then find one root using the plus instead of plus minus sign, and the other root using the minus instead of plus ...
TD
Answered by Tutor382317 D. • Maths tutor
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X is inversely proportional to Y. When X=4, Y=9. If Y=6, what is the value of X?

There are a few steps to this question. Before we can work out our value of X we will have to figure out an equation that links X and Y.Now if X were proportional to Y, then as X got bigger so would Y.We can...
AW
Answered by Andrew W. • Maths tutor
6817 Views

Hey I am having difficulties solving simultaneous equations? Please may you help me!

Yes of course. I will start with an example. Try and solve these simultaneous equations I will talk you through the model answer below. 3x + y = -4 3x - 4y = 6 Notice both equations contain 3x we can therefo...
GW
Answered by Georgina W. • Maths tutor
3099 Views

P is a point on the circle with equation x^2 + y^2 = 80. P has x-coordinate 4 and is below the x-axis.Work out the equation of the tangent to the circle at P.

Point P has x-coordinate 4, to work out the y-coordinate you should substitute x=4 into the equation of the circle. This gives you 16 + y^2 = 80. this can be rearranged to y^2 = 80 - 16 = 64. Therefore y = +...
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Answered by Faaris K. • Maths tutor
11073 Views

There are 720 boys and 700 girls in a school. The probability that a boy chosen at random studies French is 2/3 The probability that a girl chosen at random studies French is 3/5. Work out the number of students in the school who study French.

Let x denote the number of boys studying French and y the number of girls studying French. Then the probability that a boy chosen random studies French is x/720 and the probability that a randomly chosen gir...
Answered by • Maths tutor
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