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Solve the following simultaneous equations to obtain values for x and y: 2x + y = 7 & 3x - y = 8.

Label your equations 1 and 2 respectively. Make y the subject of equation 2 by taking away 3x from both sides and multiplying both sides by -1, to get y = 3x - 8. Now substitute this into equation 1 (i.e. re...
PM
Answered by Pratham M. • Maths tutor
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How do you calculate the sine, cosine and tangent values for 45 degrees without a calculator?

To find the values for 45 degrees, we construct a right angled isosceles triangle, which has two sides of equal length. We can say that these sides are 1 unit long, and so we can figure out the value of the ...
HC
Answered by Heather C. • Maths tutor
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I decrease a number by 26%, the answer is 9 x10^-7, what was the original number?

The number has been decreased by 26%, this means that the original number is 100-26=74% of the original value. Therefore 9 x 10 -7 = 0.74 x N, where N is the original number. Hence N=(9 x 10 -7 )/0.74 = 1.21...
LC
Answered by Luke C. • Maths tutor
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expand and simplify (x+3)(x-7)

(x+3)(x-7) = (x x) + (x -7) + (x 3) + (3 -7) = x^2 - 7x + 3x - 21 = x^2 - 4x - 21 Key here is to ensure you multiply each term in one bracket by both in the other, and to keep careful track of the signs.
LP
Answered by Luke P. • Maths tutor
26287 Views

How do I use Pythagoras' Theorem to calculate the hypotenuse of a triangle?

[use of board] So, Pythagoras' theorem states that a^2+b^2=c^2. Therefore, we need to mark the triangle with a, b &c. a and b do not matter, c must be the longest edge, that creates the diagonal. Put the...
CT
Answered by Cathy T. • Maths tutor
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