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Solve the quadratic equation: x^2 - 2x - 15 = 0

We need to find numbers that multiply together to give -15. This could be -1 and 15, 1 and -15, -3 and 5, 3 and -5. The numbers we need must add up to -2 as well (from -2x term). Therefore our set must be 3 ...
SK
Answered by Sabrina K. • Maths tutor
6749 Views

Factorise completely ( x − 4x^3)

(x-4x 3 ) = x(1-4x 2 ) Just taking a factor of x out of both terms Within the inner bracket we have a difference of two squares. 1 2 =1 and (2x) 2 =4x 2 therefore we can write x(1-4x 2 ) = x(1-2x)(1+2x)
EC
Answered by Edward C. • Maths tutor
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Y=3x^2-2 ( Make x the ubject of the formula

x=((y+2)/3)^1/2
TP
Answered by Talha P. • Maths tutor
4491 Views

find the values of x when 3x^2 - 6x - 9

First we will need to factorise the equation. Start with the 3x^2 term and notice 3 is prime so must have 3x and x terms. (3x - 9) (x + 1) or (3x + 3) (x - 3) Setting the brackets to 0 gives us 3x - 9 = 0 an...
DM
Answered by Dylan M. • Maths tutor
5372 Views

Solve the simultaneous equations: 4x + 7y = 1, 3x + 10y = 15.

4x + 7y = 1 1. 3x + 10y = 15 2. 1. x 3 (4x x 3) + (7y x 3) = 1 x 3 12x + 21y = 3 3. 2. x 4 (3x x 4) + (10y x 4) = 15 x 4 12x + 40y = 60 4. 4. - 3. (12x - 12x) + (40y - 21y) = 60 - 3 19y = 57 y = 57/19 y = 3 ...
IJ
Answered by Isabelle J. • Maths tutor
6380 Views