Factorise x² + bx + c when c is negative

Question 1

Factorise: x² + 10x − 24

• A. (x + 2)(x − 12)
• B. (x + 2)(x + 12)
• C. (x − 2)(x − 12)
• D. (x − 2)(x + 12)

Question 2

x² + 7x − 8 = (x + 8)(x + ☐). What number goes in the box?

Answer 

Question 3

Factorise: x² − 6x − 40

• A. (x − 4)(x + 10)
• B. (x − 4)(x − 10)
• C. (x + 4)(x + 10)
• D. (x + 4)(x − 10)

Question 4

x² − 4x − 21 = (x + 3)(x + ☐). What number goes in the box?

Answer 

Question 5

Factorise: x² + 2x − 3

• A. (x − 3)(x + 1)
• B. (x − 3)(x − 1)
• C. (x + 3)(x + 1)
• D. (x + 3)(x − 1)

Question 6

x² − 2x − 35 = (x + 5)(x + ☐). What number goes in the box?

Answer 

Question 7

Factorise: x² + 2x − 35

• A. (x + 7)(x + 5)
• B. (x − 7)(x − 5)
• C. (x − 7)(x + 5)
• D. (x + 7)(x − 5)

Question 8

x² − x − 72 = (x + 8)(x + ☐). What number goes in the box?

Answer 

Question 9

Factorise: x² + 4x − 5

• A. (x + 5)(x + 1)
• B. (x − 5)(x − 1)
• C. (x − 5)(x + 1)
• D. (x + 5)(x − 1)

Question 10

x² − x − 6 = (x + 2)(x + ☐). What number goes in the box?

Answer 

Question 11

Factorise: x² + 2x − 24

• A. (x + 6)(x + 4)
• B. (x − 6)(x + 4)
• C. (x + 6)(x − 4)
• D. (x − 6)(x − 4)

Question 12

x² − 7x − 18 = (x + 2)(x + ☐). What number goes in the box?

Answer 

Question 13

Factorise: x² − x − 30

• A. (x − 5)(x + 6)
• B. (x + 5)(x + 6)
• C. (x − 5)(x − 6)
• D. (x + 5)(x − 6)

Question 14

x² − 5x − 36 = (x + 4)(x + ☐). What number goes in the box?

Answer 

Question 15

Factorise: x² − 7x − 30

• A. (x + 3)(x + 10)
• B. (x + 3)(x − 10)
• C. (x − 3)(x − 10)
• D. (x − 3)(x + 10)

Question 16

x² − x − 42 = (x + 6)(x + ☐). What number goes in the box?

Answer