Precalculus Examples
-3−3 , 33
Step 1
Roots are the points where the graph intercepts with the x-axis (y=0)(y=0).
y=0y=0 at the roots
Step 2
The root at x=-3x=−3 was found by solving for xx when x-(-3)=yx−(−3)=y and y=0y=0.
The factor is x+3x+3
Step 3
The root at x=3x=3 was found by solving for xx when x-(3)=yx−(3)=y and y=0y=0.
The factor is x-3x−3
Step 4
Combine all the factors into a single equation.
y=(x+3)(x-3)y=(x+3)(x−3)
Step 5
Step 5.1
Expand (x+3)(x-3)(x+3)(x−3) using the FOIL Method.
Step 5.1.1
Apply the distributive property.
y=x(x-3)+3(x-3)y=x(x−3)+3(x−3)
Step 5.1.2
Apply the distributive property.
y=x⋅x+x⋅-3+3(x-3)y=x⋅x+x⋅−3+3(x−3)
Step 5.1.3
Apply the distributive property.
y=x⋅x+x⋅-3+3x+3⋅-3y=x⋅x+x⋅−3+3x+3⋅−3
y=x⋅x+x⋅-3+3x+3⋅-3y=x⋅x+x⋅−3+3x+3⋅−3
Step 5.2
Simplify terms.
Step 5.2.1
Combine the opposite terms in x⋅x+x⋅-3+3x+3⋅-3x⋅x+x⋅−3+3x+3⋅−3.
Step 5.2.1.1
Reorder the factors in the terms x⋅-3x⋅−3 and 3x3x.
y=x⋅x-3x+3x+3⋅-3y=x⋅x−3x+3x+3⋅−3
Step 5.2.1.2
Add -3x−3x and 3x3x.
y=x⋅x+0+3⋅-3y=x⋅x+0+3⋅−3
Step 5.2.1.3
Add x⋅xx⋅x and 00.
y=x⋅x+3⋅-3y=x⋅x+3⋅−3
y=x⋅x+3⋅-3
Step 5.2.2
Simplify each term.
Step 5.2.2.1
Multiply x by x.
y=x2+3⋅-3
Step 5.2.2.2
Multiply 3 by -3.
y=x2-9
y=x2-9
y=x2-9
y=x2-9
Step 6