We will encounter non-quadratic equations that are quadratic in form. We can create a quadratic equation by making a simple substitution. We can then solve the quadratic equation using the quadratic formula. When done, we substitute once more to obtain a solution in terms of the original variable involved.

Test Objectives
• Demonstrate the ability to identify a non-quadratic equation which is quadratic in form
• Demonstrate the ability to use substitution to create a quadratic equation
• Demonstrate the ability to solve an equation which is quadratic in form
Solving Equations that are Quadratic in Form Practice Test:

#1:

Instructions: Solve each using the quadratic formula.

a) $$12x^4 + 7x^2 - 45=0$$

#2:

Instructions: Solve each using the quadratic formula.

a) $$25x^4 - 10x^2 - 3=0$$

#3:

Instructions: Solve each using the quadratic formula.

a) $$3x^\frac{2}{5}- 7x^\frac{1}{5}+ 2=0$$

#4:

Instructions: Solve each using the quadratic formula.

a) $$(7x^2 - 51)^2 - 8(7x^2 - 51) - 48=0$$

#5:

Instructions: Solve each using the quadratic formula.

a) $$5x^\frac{2}{3}+ 7x^\frac{1}{3}- 6=0$$

Written Solutions:

#1:

Solutions:

a) $$x=\pm \frac{\sqrt{15}}{3}\hspace{.5em}or \hspace{.5em}x=\pm\frac{3i}{2}$$

#2:

Solutions:

a) $$x=\pm\frac{\sqrt{15}}{5}\hspace{.5em}or \hspace{.5em}x=\pm\frac{i\sqrt{5}}{5}$$

#3:

Solutions:

a) $$x=32 \hspace{.5em}or \hspace{.5em}x=\frac{1}{243}$$

#4:

Solutions:

a) $$x=\pm3 \hspace{.5em}or \hspace{.5em}x=\pm\frac{\sqrt{329}}{7}$$

#5:

Solutions:

a) $$x=-8 \hspace{.5em}or \hspace{.5em}x=\frac{27}{125}$$