The Purplemath Forums

I have not taken algebra in 20 years, and have an algebra class left to complete my associates. Ive been reviewing like crazy, but much of this is still stumping me and I feel behind so I'll be coming in here a bit to see if I can get help, and find a tutor at the college. Im making progress, but it...

I'm a litte confused over the box method. So far its been helful. http://www.purplemath.com/modules/factquad2.htm Down in the box area: 4x2 – 19x + 12 = (x – 4)(4x – 3) To the left of the box there is an x and below that a -4 http://www.purplemath.com/modules/quads/quadanim.gif Same thing with this ...

How did this factorization come to be? 8x^2\, +\, 6x\, -\, 9\, =\, 0 (4x\, -\, 3)(2x\, +\, 3)\, =\, 0 I see where 4x and 2x came from, and I under stand that -3*3=-9 for the C position, but how did the 6 get there in the B position? Isn't it supposed to be what you get when you add -...

maggiemagnet wrote:I don't understand: What do you mean by "the 6 getting into the 8 position"?

Not 8, B, A + B + C, you know...

I prefer the "magic number" way of factoring trinomials since the people I've worked with have seemed to understood it better that way. If your trinomial is in the form of ax² + bx + c, then you find two numbers that multiply to give you the product ac and that add to give you b. With you...

I am checking my answer to expand my expression:

log₃(3square root x /81)

I get:

1/3log₃ x-4

Did I do this correctly?