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The rate of decay of the mass is modelled by the differential equation dx/dt = -(5/2)x. Given that x = 60 when t = 0, solve the quation for x in terms of t.

(1) Rearrange the equation so that the left hand side is a function of x, and the right hand side is a function of t only.dx/dt = - (5/2) x(1/x)dx = -(5/2)dt(2) Integrate both sidesln(x/A) = -(5/2)t, where A...
JC
Answered by Joseph C. • Maths tutor
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Solve x^2 - 9 = 4x + 12

x 2 - 9 = 4x + 12 x 2 - 9 - 4x = 12 x 2 - 9 - 4x -12 = 0 x 2 - 4x -21 = 0 Factorise into form (x + ?)(x + ?) Factors of -21 are +7 and -3 or -7 and +3 (x + 7)(x - 3) = x 2 + 7x - 3x -21 = x 2 + 4x -21 which ...
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Answered by Kira P. • Maths tutor
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A group of 55 pupils were asked if they owned a phone or a tablet.11 people are known to own both18 said they only owned a tablet34 said they owned at least a phoneA student is picked a random, what is the probability that the student doesn’t have a phone

18/55
UH
Answered by Umer H. • Maths tutor
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What are logarithms?

Logarithms allow us to calculate and manipulate indices in relation to regular numbers. The key thing to remember is that " log x y " begs the question "which power of x gives y ". By thi...
AM
Answered by Alex M. • Maths tutor
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When will I ever need to use this in real life?

Maths is something you can make use of for the rest of your life.Obviously, there are a vast number of jobs out there, such as engineering, which use mathematics everyday so if that's the sort of thing that ...
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Answered by Alex M. • Maths tutor
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