What is the minimum value of |x-3| - |x+2.5| + |x-5|?
Which of the following is a factor of 2x^4 + 1 + 3 x^2 ?
A 1 + 2x^2
B 4+x^2
C 2x^2 -1
D 3+x^2
If x<7,then
Factorise: x^3-5x^2+2x+8