can you guys please help me with the following questions??!!!
1. Factorise:
a. $\displaystyle 8x^2 - 2x - 15$
b. $\displaystyle 2y^3 + y^2 - 2y - 1$
By inspection,
$\displaystyle 8x^2 - 2x - 15 = (2x - 3)(4x + 5) $
You could have used the quadratic formula here to find the 2 roots and thus factorise the equation.
$\displaystyle \text{Let} \,\,f(y) = 2y^3 + y^2 - 2y - 1$
Using the remainder theorem, we can see $\displaystyle f(1) = 2 + 1 - 2 - 1 = 0 $
And therefore $\displaystyle y = 1$ is a root, therefore $\displaystyle (y - 1)$ is a factor of the polynomial.
Factorising: $\displaystyle 2y^3 + y^2 - 2y - 1 = (y - 1)(2y^2 + 3y + 1) = (y - 1)(2y + 1)(y + 1)$
thanks A LOT! for the solution of the first equation....but for the second one...can you please show the long division..cuz even i understood HOW to do it....but i go wrong in the procedure....ALWAYS!!!! so i kinda needed help with that....Originally Posted by nzmathman
thanks in adv...