Trial and Error Exercises

Example 1

Factor x² + 7x – 8.

Hint

Find two numbers that multiply to -8 and add to 7.

Example 2

Factor x² + 9x + 20.

Hint

The product of the numbers we factor with needs to be 20 and the sum needs to be 9.

Example 3

Factor x² – 5x – 6.

Hint

The numbers need to multiply to -6 and add to -5. You could try to use 2 and 3, but we're telling you, it's not gonna work.

Example 4

Factor 3x² – 3x – 36.

Hint

Pull out a GCF first. Then factor what’s left. Just don’t forget about it at the end of the problem.

Example 5

Factor 4x³ + 44x² + 120x.

Hint

Pull out a GCF first. Look for a number and variable combo that's common to all terms.

Example 6

Factor x² + 5x + 4.

Hint

What numbers multiply to 4 and add to 5? They'll probably be important at some point here.

Example 7

Factor 2x² + 13x + 15.

Hint

The coefficients on the x terms have to multiply to 2x², while the constants have to multiply to 15.

Example 8

Factor 3x² + 3x – 18.

Hint

Pull out a GCF first. Just don’t lose it while you’re factoring the rest of the expression.

Example 9

Factor -6x² + 5x – 1.

Hint

The coefficients on the x terms have to multiply to -6x² and the constants have to multiply to -1.

Example 10

Factor 40x² – 46x + 12.

Hint

Pull out a GCF first. That would be a 2. Then factor what’s left. For the coefficients on the x terms, might we suggest a 4 and a 5?

Trial and Error Exercises

Example 1

Example 2

Example 3

Example 4

Example 5

Example 6

Example 7

Example 8

Example 9

Example 10

Tired of ads?