Question

Foil: (x+9)(3x-4)

Answer 1

QUESTION 1

The given binomial is;

$(x+9)(3x-4)$

First terms are multiplied: $x\times 3x=3x^2$

Outside terms are multiplied: $x\times -4=-4x$

Inside terms are multiplied: $9\times 3x=27x$

Last terms are Multiplied: $9\times -4=-36$

This gives us;

$=3x^2-4x+27x-36$

$=3x^2+23x-36$

QUESTION 2

We want to factor

$6r^5s+4r^4s^2-8r^2s$

The HCF is $2r^2s$

We factor to get;

$2r^2s(3r^3+2r^2s-4)$

QUESTION 3;

$x^2+x-2=0$

Split the middle term;

$x^2+2x-x-2=0$

Factor

$x(x+2)-1(x+2)=0$

$(x+2)(x-1)=0$

$(x+2)=0,(x-1)=0$

$x=-2,x=1$

The solutions are;

$x=-2$ and $x=1$

These are the x-intercepts of the graph of the function

$f(x)=x^2+x-2$