1. ## factorsing this expression

the expression is$\displaystyle 6a^2-a-2$

now this is what ive done.......

taken out the common factor of -ve.
1.$\displaystyle -(6a^2+a+2)$

2. $\displaystyle -[(6a^2+a+12)]$

3. $\displaystyle -[(6a^2+4a-3a+12)]$

4. $\displaystyle -[2a(3a+2)-3(a-4)]$

2. Originally Posted by johnsy123
the expression is$\displaystyle 6a^2-a-2$

now this is what ive done.......

taken out the common factor of -ve.
1.$\displaystyle -(6a^2+a+2)$

2. $\displaystyle -[(6a^2+a+12)]$

3. $\displaystyle -[(6a^2+4a-3a+12)]$

4. $\displaystyle -[2a(3a+2)-3(a-4)]$
You don't need to take out a negative common factor, because the first value is already positive...

You need 2 numbers that multiply to become $\displaystyle 6(-2) = -12$ and add to become $\displaystyle -1$.

The two numbers are $\displaystyle -4$ and $\displaystyle 3$.

$\displaystyle 6a^2 - a - 2 = 6a^2 - 4a + 3a - 2$

$\displaystyle = 2a(3a - 2) + 1(3a - 2)$

$\displaystyle = (3a - 2)(2a + 1)$.

3. Assuming the equation you have written is correct:

$\displaystyle 6a^2 - a - 2$

$\displaystyle 6a^2 + 3a - 4a - 2$

$\displaystyle 3a(2a + 1) - 2(2a + 1)$

$\displaystyle (3a - 2)(2a + 1)$