Question

How do you group 2x² + 13x + 21 ?

Answer 1

Given that your quadratic is in the form of ax^2 + bx +c, multiply ac to get 42. Find factors of 42 that add to 13 (the b coefficient). Substitute those coefficients for the middle term, then factor by grouping. In this case, those factors are six and seven.\[2x² + 13x + 21=2x^2+6x+7x+21\]\[=2x(x+3)+7(x+3)=(2x+7)(x+3)\]

Answer 2

Thank you so much!

Answer 3

Do you get it?

Answer 4

Kind of. For every trinomial like this do you rewrite the middle term?

Answer 5

Not every trinomial will be factorable. This method only works if the zeros of the function are rational numbers (fractions).

Answer 6

Okay

Answer 7

This method is usually only used for problems that have a leading coefficient (a) different than one.

Answer 8

Do math every day.

Answer 9

Okay thanks