2007-05-07 12:35:26 · 5 answers · asked by pretty l 1 in Science & Mathematics ➔ Mathematics
(4x-5)(x+2)
Since the x-term has a coefficient of 3, you know it's not an answer of the form (2x+a)(2x-b), because in that case the x-term would be 2a-2b, or an even number.
That means the factored equation is probably of the form (4x+a)(x+b), where one of a and b is negative, and their product is -10, and 4b-a equals +/-3.
Choosing 2 and 5 as sensible factors of 10, and mutiplying the smaller one (2) by 4, we see that we can generate the difference of three. (4*2)-5 = 3, so we know that works if the "5" is with 4x and the 2 is with x.
You could solve it rigorously with the quadratic formula or something like that, but it's pretty easy to puzzle these ones out by looking at the constant values in the equation and their signs.
2007-05-07 12:38:20 · answer #1 · answered by McFate 7 · 1⤊ 0⤋
Ok, couple of ways of doing it... you are better of using the factoring method
the two factors are
(x+2) ( 4x - 5)
2007-05-07 12:42:56 · answer #2 · answered by sudhi_kandi 3 · 0⤊ 0⤋
4x^2+3x-10
= 4x^2+8x-5x-10
= 4x(x+2)-5(x+2)
= (4x-5)(x+2)
2007-05-07 12:40:30 · answer #3 · answered by sahsjing 7 · 0⤊ 0⤋
(4x-5)(x+2)=0
4x-5=0
x+2=0
x=5/4 x=-2
2007-05-07 12:41:38 · answer #4 · answered by Dave aka Spider Monkey 7 · 0⤊ 0⤋
4x^2+3x-10
(4x^2+8x)-(5x-10)
(4x^2+8x)-(5x+10)
4x(x+2)-5(x+2)
(4x-5)(x+2)
2007-05-07 12:43:05 · answer #5 · answered by bluebird_chica 2 · 0⤊ 0⤋