Similar to solving quadratics we have a few methods to choose between when solving cubic equations:
When factorising a cubic recall we can factorise by:
Solve the equation $x^3=-8$x3=−8.
Solve the equation $\left(x+8\right)\left(x+4\right)\left(1+x\right)=0$(x+8)(x+4)(1+x)=0.
State the solutions on the same line, separated by commas.
Solve the equation $x^3-49x=0$x3−49x=0.
State the solutions on the same line, separated by a comma.
The cubic $P\left(x\right)=x^3-2x^2-5x+6$P(x)=x3−2x2−5x+6 has a factor of $x-3$x−3.
Solve for the roots of the cubic. If there is more than one root, state the solutions on the same line separated by commas.
Use technology to solve the cubic equation $48x^3-212x^2+84x+209=-36$48x3−212x2+84x+209=−36.
If there is more than one root, state the solutions on the same line separated by commas.