2007-06-26 06:09:15 · 7 answers · asked by iAmJustMe 2 in Education & Reference ➔ Homework Help
the answer is ....
(3x-5)(x+5)=>
3x-5=0 => x=5/3
x+5=0 => x=-5
and then choose the suitable answer.
2007-06-26 06:16:52 · answer #1 · answered by Engineer.Njood 2 · 1⤊ 0⤋
Use the FOIL method
First
Outside
Inside
Last
3x^2+10x-25
(3x-5)(x+5)
2007-06-26 13:12:22 · answer #2 · answered by Carmen 4 · 3⤊ 0⤋
All the answers posted so far actually find the factors.
But to answer your question without doing this,
use the following rule:
If y = ax² + bx + c
can be factored over the rationals, then
b² -4ac must be a square.
In your case b²-4ac = 100 + 4(3)(25) = 400 = 20²,
so the answer is "yes".
2007-06-26 14:53:26 · answer #3 · answered by steiner1745 7 · 0⤊ 0⤋
When you consider this quadratic equation,the product has to be -75 and the sum has to be +10.SO think of 2 numbers whose sum is +10 and product is -75.The numbers are +15 and -5.Now split the middle term.
Therefore,
3x^2+15x-5x-25=0
3x(x+5)-5(x+5)=0
(x+5) (3x-5)=0
x=-5 or x=5/3.
So,there you go.
2007-06-26 13:23:59 · answer #4 · answered by motorockr:luv the thump 4 · 0⤊ 0⤋
delta=100-4*3*(-25)=400
x'1=(-10+20)/6=10/6=5/3
x'2=(-10-20)/6=(-30)/6=-5
2007-06-26 13:25:18 · answer #5 · answered by Alexandra 1 · 0⤊ 0⤋
quadratic eqn:
(-b +/- sqrt(b*b - 4ac)) / (2a)
a = 3
b = 10
c = -25
factors to
(x-5)*(x+5/3)
2007-06-26 13:20:02 · answer #6 · answered by Anonymous · 0⤊ 0⤋
yes, but you must do your own homework
2007-06-26 13:18:39 · answer #7 · answered by Anonymous · 0⤊ 0⤋