- NEW!
by 10marks on March 18th, 2010
x^2 - 2x - 15
x^2 - 2x - 15 is of the form x^2 + bx + c.
To factor a quadratic trinomial of the form x^2 + bx + c, find two integer factors of 'c' whose sum is 'b'.
If no such integers exist, we say the trinomial is not factorable.
b = -2 and c = -15
Note: When 'b' is positive, the factors are positive, and when 'b' is negative, the factors are negative.
x^2 - 2x - 15 = (x + __)(x + __)
Look for factors of -15 whose sum is -2.
Factors of -15 Sum
1 and -15 -14
3 and -5 -2
The factors needed are 3 and -5.
x^2 - 2x - 15 = (x + 3)(x + (-5))
= (x + 3)(x - 5)
Check:
(x + 3)(x - 5) = x . x + 3 . x + (-5) . x + 3 . (-5) [FOIL Method]
= x^2 + 3x - 5x - 15
= x^2 - 2x - 15 [The product is the original trinomial]"
by commonsenseisknocking on January 28th, 2010
X^2 = (X ) (X )
whats multiplies to -15, adds too -2
+5, -3
(x-5)(x+3)
Math question found in +venture in math (s'pore)
by HANz318 on October 30th, 2011
| 1 person likes this
346 is the given number must be divisible by 3. what is the missing greatest number?
by Franz_P on September 26th, 2011
| 1 person likes this
How big would the earth have to be to exert half of the gravity on us? Specifically what ratio of volume so we would weigh half as much?
by Ombliss22 on September 25th, 2011
| 1 person likes this
Can you do this for me smallest to largest!! 0.3 , 0.109 , 0.1
0.19 , 0.903 , 0.9 , 0.91 , 0.09
by Elisha_S7421 on September 29th, 2011
| 1 person likes this
what is the vertex of thsi problem!! g(x) =x^2+8x-1
by Anonymous on September 27th, 2011
| 1 person likes this
You're reading how do i solve x^2-2x-15=0?
Your favorite Q&A site is on Facebook! Become a fan to connect with the ever-growing community of Answerbaggers, share your thoughts and find out what Answerbag's up to next!
Comments