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John has 12 marbles. Sandra has 10 more marbles than Kathy. Kathy has 4 times as many marbles as John. How many marbles does Sandra have?

This question asks how students can formulate linear equations from worded questions. The first step is to give each person an algabraic symbol. j for John, s for Sandra and k for Kathy works fine. Next, stu...
JW
Answered by James W. • Maths tutor
5707 Views

How do you differentiate x^x?

To differentiate x x , we first let y = x x . ( Note that x x is not in the form x c where c is a constant or a x where a is a constant so the usual differentiation formulas cannot be used ). The trick here ...
AP
Answered by Anish P. • Maths tutor
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The straight line with equation y = 3x – 7 does not cross or touch the curve with equation y = 2px^2 – 6px + 4p, where p is a constant. Show that 4p^2 – 20p + 9 < 0.

The main piece of information this question gives us is that the two lines do not cross or touch. From this we can immediately see that we will need to use the discriminant of the quadratic formula b 2 - 4ac...
MW
Answered by Molly W. • Maths tutor
27839 Views

Let f(x) = 2x^3 + x^2 - 5x + c. Given that f(1) = 0 find the values of c.

In order to solve this question we simply must substitute x=1 into f(x). If we carry out this substitution we see that f(1) = 2(1^3) + (1^3) -5(1) + c = 2(1) + (1) -5(1) + c = 2 + 1 - 5 + c = 3 - 5 + c = c -...
CL
Answered by Calum L. • Maths tutor
4201 Views

I have a bag with 4 different coloured marbles. Blue, green, red, and orange. I have 2x,7,7x + 5,4x -3 of each coloured marble respectively. If the probability of a green marble being picked is 7/100, find the probability of an orange marble being picked.

Let's reorgansie the information we've been provided with in the question: Colour of marble - number of marbles in the bag Blue - 2x Green - 7 Red - 7x + 5 Orange - 4x - 3 Probability of the green marble bei...
GM
Answered by Georgina M. • Maths tutor
5303 Views