can someone explain how to do this question please!!?

Question

b(squared) - b - 12 = 0

i think you have to complete tthe square but i really dont understand pleasse help!!!

Answer 1

b^2 -b -12 = 0
(b + 3) (b - 4) = 0

b = -3 or 4

So how did I do that.

A quadratic factors into 2 binomial terms, that when multiplied together (FOIL method) return to the original quadratic.

The last value (-12) tells me that The factors of 12 have to have a different sign.

The coefficient of b (-1) tells me that the bigger factor of 12 must be negative and the difference between the factors must be one.

Answer 2

b^2 -b -12 = 0
can be factored as:
(b-4)(b+3) = 0
b =4 or -3
If you have to complete the square: remember
b^2 -2ab + a^2 = (b - a)^2

think of:
b^2 -b as the first two terms:
and
b^2 -b = 12
add a^2 to both sides where a = -1/2 dividing the coefficient of the second term by 2.
a^2 = 1/4 so:
b^2 -b + 1/4= 12 + 1/4
b^2 -b + 1/4= 49 /4
(b - 1/2) = 49/4
taking the square root of both sides:
b - 1/2 = ± 7/2
b = 1/2 ± 7/2
b = 8/2 or - 6/2
b = 4 or -3

Answer 3

b=4

Answer 4

4 or -3

Answer 5

The factors of 12 that would add to -1 is what you are looking for (before having to worry about completing the square), so you can factor this as it is.

The two numbers that add to -1 and multiply to -12 are -4, 3

So...

(b - 4)(b + 3) = 0

The solutions for b are therefore {4, -3}

As a side note, you can notate "b(squared)" as b^2.

Good luck!

Answer 6

Yes, we have to use the quadratic formula i.e. you have to factorize the given equation.

b(square)-b-12=0
The co-efficient of 'b' is 1, now multiply it with12 you will get 12 as answer.

Now find the factors for 12
The factors are
1*12
2*6
3*4
There are six factors for 12.
Above there are 3 lines na, now see for which by adding or subtracting you will get the co-efficient of the middle term.
here , in the third lineby subtracting 3 from 4 you will get 1.

Now substitute in them in the equation, you will get
b(square)-3b+4b-12=0
It can also be written as
b(b-3)+4b-12=0
This can also be written as b(b-3)+4(b-3)=0
=(b+4) (b-3)=0
=b+4=0, b-3=0
You will get 2 different values for b, According to the usage of this equation you can choose one answer as you get one positive answer and one negative answer.

Answer 7

(a+b)x(a+b)= axa + 2 x a x b + b x b,
That's the general formula.
y= b x b + 2 x a x b + b x b this is the formula for a parabola
then there's the quadratic formula.
In the FORMULAS I've listed above, the b in your equation corresponds to the a in mine. Look for these formulas in your book and see if tere's an example there that will help you with your particular EQUATION. Great! The young geniuses above solved it. What you have is a parabola cutting the x-axis at (-3,0) and at (4,0)

Answer 8

You are looking for the solution to what b is...
b=4
4squared-4-12=0

Answer 9

b^2 - b - 12 = 0

b -4 (find factors of -12 that can add up to -b )
b +3

(b-4)(b+3)=0

b= 4 , b= -3

Answer 10

B^2 - B - 12 = 0

(B-4)(B+3)

b=4
b=-3