Factor by grouping

Answer Key - Grade 9 Math Worksheet

Circle the best answer, or write your answer on the line.

1. 1.

   Milo groups 2x³ − 6x² − 5x + 15 = 2x²(x − 3) + ▢(x − 3). It may be negative. What number goes in the box?

   -5
2. 2.

   Noah writes x³ − 4x² − 7x + 28 as x²(x − 4) + ▢(x − 4). It may be negative. What number goes in the box?

   -7
3. 3.

   Pia wants both brackets to be x − 2: 3x³ − 6x² − 4x + 8 = 3x²(x − 2) + ▢(x − 2). It may be negative. What goes in the box?

   -4
4. 4.

   Ren groups 2x³ − 10x² − 3x + 15 as 2x²(x − 5) + ▢(x − 5). It may be negative. What number goes in the box?

   -3
5. 5.

   Tala splits 10x² + 23x + 12 into 10x² + 15x + 8x + 12. Grouped, it is 5x(2x + 3) + ▢(2x + 3). What number goes in the box?

   4
6. 6.

   Zee cuts the middle piece of 6x² + 31x + 40: 6x² + 15x + 16x + 40. Grouped, it is 3x(2x + 5) + ▢(2x + 5). What goes in the box?

   8
7. 7.

   Ari writes 12x² + 35x + 18 as 12x² + 8x + 27x + 18, then groups it as 4x(3x + 2) + ▢(3x + 2). What number goes in the box?

   9
8. 8.

   Esme factors x³ − 2x² − 7x + 14 by grouping. Which answer is right?

   • (x − 2)(−7x²)
   • x²(x − 2) − 7(x − 2)
   • (x − 2)(x² + 7)
   • (x − 2)(x² − 7)
9. 9.

   Jun groups x³ − 6x² − 5x + 30 in two pairs. Which shows it as one product?

   • x²(x − 6) − 5(x − 6)
   • (x − 6)(x² − 5)
   • (x − 6)(x² + 5)
   • (x − 6)(−5x²)
10. 10.

    Luz checks four answers for x³ + 4x² − 6x − 24, factored by grouping. Which one is right?

    • (x + 4)(x² + 6)
    • (x + 4)(−6x²)
    • (x + 4)(x² − 6)
    • x²(x + 4) − 6(x + 4)