Example

Factoring 10y255y+7010y^2 - 55y + 70

Factor 10y255y+7010y^2 - 55y + 70 completely by first extracting the GCF and then factoring the remaining trinomial whose leading coefficient is not 1.

Step 1 — Check for a GCF. The three terms 10y210y^2, 55y-55y, and 7070 share a common factor of 55. Factor it out:

10y255y+70=5(2y211y+14)10y^2 - 55y + 70 = 5(2y^2 - 11y + 14)

Be careful to keep this factor of 5 throughout the rest of the solution.

Step 2 — Factor the trinomial inside the parentheses. The expression 2y211y+142y^2 - 11y + 14 is a trinomial with leading coefficient a=21a = 2 \neq 1, so use trial and error or the ac method. The factored form is:

5(y2)(2y7)5(y - 2)(2y - 7)

Step 3 — Check by multiplying all three factors:

5(y2)(2y7)=5(2y27y4y+14)=5(2y211y+14)=10y255y+705(y - 2)(2y - 7) = 5(2y^2 - 7y - 4y + 14) = 5(2y^2 - 11y + 14) = 10y^2 - 55y + 70

The completely factored form is 5(y2)(2y7)5(y - 2)(2y - 7). This example reinforces the importance of always checking for a GCF first — and of keeping the GCF factor throughout the entire solution. After extracting the GCF of 5, the remaining trinomial still has a leading coefficient of 2, requiring a method for ax2+bx+cax^2 + bx + c with a1a \neq 1. Without factoring out the 5 first, the larger coefficients in 10y255y+7010y^2 - 55y + 70 would make the trinomial factoring much more difficult.

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Updated 2026-04-29

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