Question

factorise y^2-13y+12

Answer 1

${y}^{2} - 13y + 12$

You can solve it using several methods. I'm using the biquadratic formula.... ^^

Biquadratic formula = $\frac{ - b \: + - \: \sqrt{b {}^{2} - 4ac } }{2a}$

Here,

• a = 1
• b = -13
• c = 12

Now using it...

$y=\frac{-\left(-13\right)±\sqrt{\left(-13\right)^{2}-4\times 12}}{2} \\ y=\frac{-\left(-13\right)±\sqrt{169-4\times 12}}{2} \\ y=\frac{-\left(-13\right)±\sqrt{169-48}}{2} \\ y=\frac{-\left(-13\right)±\sqrt{121}}{2} \\ y=\frac{-\left(-13\right)±11}{2} \\y=\frac{13±11}{2}$

Now, solve for the positive value .

$y=\frac{13 + 11}{2} \\ y=\frac{24}{2} \\ \boxed{ y=12 }$

Now, solve for the negative value.

$y = \frac{13 - 11}{2} \\ y=\frac{2}{2} \\ \boxed{y = 1}$

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Answer 2

Answer:

y^2-13y+12=y^2-12y-y+12

                 =y(y-12)-1(y-12)

                 =(y-12)(y-1)