Identify GCF: Identify the greatest common factor (GCF) of the terms in the polynomial 5x3+55x2+120x. The GCF of 5x3, 55x2, and 120x is 5x, since each term is divisible by 5x. Factor out the GCF from each term.
Factor out GCF: Write the polynomial as a product of the GCF and the remaining terms.5x3+55x2+120x=5x(x2+11x+24)Check that the terms inside the parentheses are correct by distributing 5x back to each term.5x(x2)+5x(11x)+5x(24)=5x3+55x2+120x, which matches the original polynomial.
Write as product: Factor the quadratic expression inside the parentheses.The quadratic x2+11x+24 can be factored into two binomials because it is a simple trinomial.Find two numbers that multiply to 24 and add to 11. These numbers are 8 and 3.Write the factored form of the quadratic: (x+8)(x+3).
Factor quadratic: Combine the GCF with the factored quadratic to write the completely factored form of the original polynomial.5x3+55x2+120x=5x(x+8)(x+3)Check that the factored form is correct by expanding the binomials and multiplying by 5x to see if it gives the original polynomial.5x(x+8)(x+3)=5x(x2+11x+24)=5x3+55x2+120x, which is correct.
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