Mister Exam
Factor -b^2-b+3 squared
The solution
The perfect square
Let's highlight the perfect square of the square three-member
$$\left(- b^{2} - b\right) + 3$$
To do this, let's use the formula
$$a b^{2} + b^{2} + c = a \left(b + m\right)^{2} + n$$
where
$$m = \frac{b}{2 a}$$
$$n = \frac{4 a c - b^{2}}{4 a}$$
In this case
$$a = -1$$
$$b = -1$$
$$c = 3$$
Then
$$m = \frac{1}{2}$$
$$n = \frac{13}{4}$$
So,
$$\frac{13}{4} - \left(b + \frac{1}{2}\right)^{2}$$
$$\left(- b^{2} - b\right) + 3$$
To do this, let's use the formula
$$a b^{2} + b^{2} + c = a \left(b + m\right)^{2} + n$$
where
$$m = \frac{b}{2 a}$$
$$n = \frac{4 a c - b^{2}}{4 a}$$
In this case
$$a = -1$$
$$b = -1$$
$$c = 3$$
Then
$$m = \frac{1}{2}$$
$$n = \frac{13}{4}$$
So,
$$\frac{13}{4} - \left(b + \frac{1}{2}\right)^{2}$$
Factorization
[src]
/ ____\ / ____\ | 1 \/ 13 | | 1 \/ 13 | |b + - - ------|*|b + - + ------| \ 2 2 / \ 2 2 /
$$\left(b + \left(\frac{1}{2} - \frac{\sqrt{13}}{2}\right)\right) \left(b + \left(\frac{1}{2} + \frac{\sqrt{13}}{2}\right)\right)$$
(b + 1/2 - sqrt(13)/2)*(b + 1/2 + sqrt(13)/2)