Grade 9 · Algebra & functions

Factoring quadratics practice

Factoring quadratics is a grade 9 math skill aligned to Common Core standard HSA.SSE.A.2: use the structure of an expression to identify ways to rewrite it. Below are 8 practice questions with answers and step-by-step explanations, drawn from the 30 factoring quadratics problems our math games drill.

CCSS HSA.SSE.A.230 questions in the bank
Sample questions

Try 8 for free

Question 1easy

x29=(xc)(x+c)x^{2} - 9 = (x - c)(x + c) with c>0c > 0. What is cc?

Difference of squares: x29=(x3)(x+3)x^{2} - 9 = (x - 3)(x + 3), so c=3c = 3.

Question 2easy

x2+kx+18x^{2} + kx + 18 factors as (x3)(x6)(x - 3)(x - 6). What is kk?

Expanding, (x3)(x6)=x29x+18(x - 3)(x - 6) = x^{2} - 9x + 18, so k=3+(6)=9k = -3 + (-6) = -9.

Question 3easy

x2+5x+6=(x+a)(x+b)x^{2} + 5x + 6 = (x + a)(x + b) with a<ba < b. What is aa?

Two numbers that multiply to 66 and add to 55 are 22 and 33, so a=2a = 2 and b=3b = 3.

Question 4easy

6x2+9x=3x(2x+c)6x^{2} + 9x = 3x(2x + c). What is cc?

Dividing each term by the common factor 3x3x gives 6x2÷3x=2x6x^{2} \div 3x = 2x and 9x÷3x=39x \div 3x = 3, so c=3c = 3.

Question 5easy

Factor: x2+7x+12x^2 + 7x + 12.

Find two numbers that multiply to 12 and add to 7: 33 and 44.

Question 6easy

Solve x25x+6=0x^{2} - 5x + 6 = 0 by factoring and enter the larger solution.

x25x+6=(x2)(x3)=0x^{2} - 5x + 6 = (x - 2)(x - 3) = 0, so x=2x = 2 or x=3x = 3; the larger solution is 33.

Question 7easy

x225=(x+d)(xd)x^{2} - 25 = (x + d)(x - d) with d>0d > 0. What is dd?

Difference of squares: x225=(x+5)(x5)x^{2} - 25 = (x + 5)(x - 5), so d=5d = 5.

Question 8easy

x26x+cx^{2} - 6x + c factors as (x1)(x5)(x - 1)(x - 5). What is cc?

Expanding, (x1)(x5)=x26x+5(x - 1)(x - 5) = x^{2} - 6x + 5, so c=(1)(5)=5c = (-1)(-5) = 5.

Drill it inside a game.

The free placement test finds your level, then every match serves factoring quadratics questions at exactly the right difficulty.