Question

Ginny factored 6x2 – 31x – 30 as shown:

ac = –180 and b = 31
36(–5) = –180 and 36 + (–5) = 31
6x2 + 36x – 5x – 30
6x(x + 6) – 5(x + 6)
(x + 6)(6x – 5)
Determine if Ginny factored correctly. If not, explain where she made an error.

Ginny made a mistake in step 1 when she identified b = 31. It should be b = –31.
Ginny was correct until step 3 when she used 36 and –5 as the coefficients of x.
Ginny was correct until step 4 when she incorrectly factored the GCF from 5x – 30.
Ginny factored the trinomial correctly.

Answer 1

Answer:

  (a)  Ginny made a mistake in step 1 when she identified b = 31. It should be b=–31.

Step-by-step explanation:

The value of b is the coefficient of x. In the given quadratic expression, the coefficient of x is -31, so Ginny should have started with b = -31 in step 1.

Answer 2

Answer:

A

Step-by-step explanation: