🔢 Algebra
Slide and Divide — Factoring ax² + bx + c when a ≠ 1
Slide and Divide — Factor hard trinomials with a leading coefficient
1
Slide — multiply a and c
Multiply the leading coefficient (a) and the constant (c) together.
2
Factor using that product
Find two numbers that multiply to give you the a×c product and add to give you b, just like factoring a simple trinomial.
3
Divide — divide by a
Divide those two numbers by the original leading coefficient a.
4
Simplify
Reduce any resulting fractions, and if a whole number is left in a denominator, move it in front of the variable as a coefficient instead.
1
Factor 2x² + 7x + 3, where a = 2, b = 7, c = 3. Slide: multiply a × c = 2 × 3 = 6.
2
Find two numbers that multiply to 6 and add to 7: those numbers are 6 and 1.
3
Divide: 6/2 = 3 and 1/2. Since 1/2 has a in the denominator still, move the 2 in front of x instead, giving (x + 3)(2x + 1).
4
Check by FOILing (x + 3)(2x + 1): 2x² + x + 6x + 3 = 2x² + 7x + 3 — matches the original.

Exams test whether you can execute all four slide-and-divide steps correctly, especially the final simplification step where a leftover fraction needs to become a coefficient rather than being left as a fraction.

The most common trap is forgetting the final simplification step — leaving a fraction in one of the factors instead of moving the denominator to become the variable's coefficient.

1. What is the first step of Slide and Divide?
Multiply the leading coefficient (a) and the constant (c) together.
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2. Factor 2x² + 7x + 3 using slide and divide.
(x + 3)(2x + 1).
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3. When is slide and divide needed instead of simple factoring?
When the leading coefficient a is not equal to 1.
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4. What do you do if dividing leaves a fraction like 1/2 in a factor?
Move the denominator to become the coefficient of the variable instead of leaving a fraction.
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5. How can you verify a slide-and-divide factoring result?
FOIL the factored answer back out and confirm it matches the original trinomial.
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