Question

Factor 1 and 2. You do NOT need to show or explain steps for 1-2.

Answer number 3 with an explanation to A-C. Provide answers in answer sheet section on the 2nd page.
x2 + 9x + 18
x 2 + 16 x + 63
Lyndsey was factoring the following trinomial:
y 2 + 13 y + 36
Her answer was (y+6)(y+6).

a.Explain to her why you know that is a wrong answer.
b.What would the factors be?
c.How do you know?

Answer 1

Explanation:

x² + 9x + 18 = x² + 6x + 3x + 18

= x(x + 6) + 3(x + 6)

= (x + 3)(x + 6)

x² + 16x + 63 = x² + 9x + 7x + 63

= x(x + 9) + 7( x+ 9)

= (x + 7)(x + 9)

y² + 13y + 36 = y²+ 9y + 4y + 36

= y(y + 9) + 4(y + 9)

= (y + 4)(y + 9)

(a). Factored form of the expression (y² + 13y + 36) is (y + 4)(y + 9).

Therefore, Lyndsey's answer is wrong.

(b). Factors are (y + 4) and (y + 9).

(c). Factored form of the expression should be (y + 4)(y + 9) instead of Lindsey's answer (y + 6)(y + 6).