how do you factor 2x^2 +11x +15= 0?

Question

if you can, show work for it please

dont use quad equation but show work please

Answer 1

2x^2 + 11x + 15 = 0
2x^2 + 6x + 5x + 15 = 0
2x(x + 3) + 5(x + 3) = 0
(2x + 5)(x + 3) = 0

x = -5/2 , x = -3

To factor a quadratic equation(ax^2 + bx + c), split 'b' into two numbers whose product equals the product of 'a' and 'c'.

Answer 2

I do it by trial and error.
First off you want to get two factor terms when multiplied together
produce 2X^2 + 11X + 15
try (aX + b) (cX + d) and I do not yet know what the values are for a,b,c & d
The a * c must equal 2
The b * d must equal 15
The b*c + a*d = 11
lets try a=1, then c=2
(x + b)(2X + d)
now 2b + d = 11 and b*d = 15
I know 3*5 = 15
lets try b=3 and d=5
substitute into 2b + d = 11
2*3 + 5 = 11 is true
(x + 3)(2x + 5) is the answer

check the answer by multiplication of the factors
2X^2 + 6X + 5X + 15
2x^2 + 11X + 15
Yep, I did it correctly.

Answer 3

Hi,
Let's factor it using something sometimes called the inverse FOIL method.
2x² +11x +15 = 0
1) First make two sets of parentheses and factor 2x² as the first terms in the parentheses. Since all of the terms in the quadratic are positive, we can also follow each factor with a positive sign.
(2x + ) (x + )

Now, for the factors after the positive signs, we want two factors of 15 such that the product of the inside terms plus the product of the outside terms equals the middle term of the quadratic, 11x.
So, some factors of 15 are 1,15; 3, 5. We can stop there, because 2x * 3 + 5*x = 6x +5x = 11x
(2x + 5) (x + 3 ) = 0

Hope this helps.
FE

Answer 4

I just learned a newe way to this I hope it helps. You take the first term (2) and the last term (15) and multipy them. (2*15=30) Then you look at all the factors [(1,30)(2,15)(3,10)(5,6)] and try to come up with the second term (11) by either adding or subtracting the coupled factors. So 5+6 equals 11. So we take the factors of 2 (1,2) and the factors of 15 (3,5) to make the 5+6 combination. (2x+5)(x+3)

Answer 5

(2x+5)(x+3)
Factoring takes practice. Firstly, look at the first two terms and set up
(ax + _)(bx + _) so that filling in the blanks gives the correct first and third terms; now if it is not correct, then switch the blank terms and see if that works. If that does not work, try changing every term. After some practice, you'll see that for stuff like this, it is easy. But, like everything else, it is easy when you know how to do it.

Answer 6

(2x + 5) (x + 3) = 0
x = - 5 / 2 , x = - 3
Working
2x X x = 2x²
5 X 3 = 15
5x + 6x = 11x

Answer 7

( 2x + 5 )( x + 3 ) = 0
so 2x+5=0 or x+3=0
x=-5/2 or x = -3

Answer 8

you have to find numbers that will add up to 11 when you use one twice and multiply to 15. ie a+a+b = 11 and ab = 15

A and B could be 5 and 3 or they could be 15 and 1.
Which pair could be used in a+a+b=11?

What you end up with is (2x + b)*(x + a)

Answer 9

this is how u go (might be wrong)

2x^2 + 11x + 15 = 0
2x^2 + 11x = 15
x(2x + 11) = 15
x = 15/(2x + 11)