-4
equals plus 5
5
Five.
-5
f(x) = x2-4x-5 = x2-5x+x-5 = x(x-5)+1(x-5) = (x+1)(x-5) Factors of f(x) are (x+1) and (x-5).
x-1+5=2x-1 becomes -x = -5 so x=5
9
1 x -5 = -5 -1 x 5 = -5
x3 + 5x2 - x - 5 = (x2 - 1)(x + 5) = (x + 1)(x - 1)(x + 5)
the pairs are 1 x 25 5 x 5
80 x/5 = 16 x/5 x 5/1 = 16 x 5/1 x = 80
1 x 1 x 175 1 x 5 x 35 1 x 7 x 25 5 x 5 x 7
x/12 = 1/5 x = 12(1/5) x = 12/5 x = 2 2/5
4x2 - x - 5 = 0 4x2 + 4x - 5x - 5 = 0 4x(x + 1) - 5(x + 1) = 0 (4x - 5)(x + 1) = 0 4x - 5 = 0 or x + 1 = 0 4x = 5 or x = -1 x = 5/4 o x = -1
1 x 75, 3 x 25, 5 x 15, 15 x 5, 25 x 3, 75 x 1
This is relatively easy to solve, only requires application of the laws of indices. (x+5)1/5 - (x+5)6/5 = 0 => (x+5)1/5 - (x+5)(x+5)1/5 = 0 => (x+5)1/5 (1 - (x+5)) = 0 => -(x+5)1/5 (x+4)=0 since the expression equals 0 one term or the other has to be 0 therefore x= -4 or x= -5