Factor
To go about the first one please show me the steps. Thanks
1.$\displaystyle (x+5)^4(x-9)^3+(x+5)^4(x-9)^4$
$\displaystyle (x+5)^4(x-9)^3[(1)+(x-9)]$?
2.$\displaystyle x^4-15x+144$
Prime?
See the graph.
Not that you needed confirmation, but the discriminant (once you've made Zach's substitution) would have told you at a glance.