SOLUTION: Ok, I have 4 more problems on my Graphing Quadratics worksheet. And it's just factoring the equation. Here's one I don't understand:
7x^2 - 43x - 42 = 0
I forget how to facto
Question 757114: Ok, I have 4 more problems on my Graphing Quadratics worksheet. And it's just factoring the equation. Here's one I don't understand:
7x^2 - 43x - 42 = 0
I forget how to factor that problem, and a few of these:
7a^2 - 59a + 24 = 0
5n^2 + 31n - 28 = 0
5v^2 - 8v - 21 = 0
Help me with this, and more tips to factor faster? Thanks so much! I need it for my Algebra 1 class. Answer by josgarithmetic(39613) (Show Source):
Requiring two binomials, one with leading term 7x and other with leading term x.
The -42 contant term in the trinomial means you need to find which factorizations of -42 will make the two binomials work.
42=2*21
42=6*7
42=3*14
maybe also 42=1*42
You may need 6 to 8 combinations to try. You could also try synthetic division if you know it, but not likely if you're just in Algebra 1.
Trying: (7x_____2)(x____21_)
2x and 63x ?
No, not work.
Try: (7x_____21)(x_____2)
21x and 14x
No.
Try: (7x____3)(x____14)
3x and 98x
NO.
Try: (7x_____14)(x_____3)
7x and 14x
Not useful.
Try: (7x____6)(x_____7)
6 and 49
Looks like might work.
NOW Which sign goes where? You want 6 and 49 somehow to give you -43.
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