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Label the equations (1): 2x + 3y = 4 (2): 3x + 6y = 3We need the same number of x's or y's in the equations, so multiply (1) by 3 and (2) by 2 giving (3): 6x + 9y = 12 (4): 6x + 12y = 6Subtract (3) from (4) ...

Skew lines in 3 dimensions are those which are not parallel and do not intersect. Let's take two example lines: l 1 = (2, 2, -1) + λ(3, 1, -3) and l 2 = (1, 0, 1) + µ(6, -4, 9) First we need to show that the...

We need two numbers, a and b, such that a*b = 2 and a+b=3Looking at the equation it can be seen that 2 and 1 fulfill these conditions.Therefore x 2 +3x +2=0 = (x+2)(x+1)=0This means we need either x+2 or x+1...

Often quadratic equations of the form a x 2 + b x+ c =0 can be easily solved by factorising. First, find pairs of numbers that multiply together to make c . Note that if c is positive, the two numbers will h...

f(c) means let x=c. Remember that c is just an unknown number. The expression f(c)=9 means that when we put c through the function f(x)=7-4x, it gives the answer 9. Therefore we know 7-4c=9 is true. Now we h...