How do you factor $8x^2+18x+9$ ?

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Answer 1 · 2015-05-02T06:36:42

We can Split the Middle Term of this expression to factorise it

In this technique, if we have to factorise an expression like $ax^2 + bx + c$ , we need to think of 2 numbers such that:

$N_1*N_2 = a*c = 8*9 = 72$
AND
$N_1 +N_2 = b = 18$

After trying out a few numbers we get $N_1 = 12$ and $N_2 =6$

$12*6 = 72$ , and $12+6= 18$

$8x^2+18x+9 = 8x^2 + 12x +6x + 9$

$= 4x(2x + 3) + 3(2x+3)$

$2x+3$ is a common factor to each of the terms

$=color(green)( (2x+3)(4x+3)$

How do you factor 8x^2+18x+98x^2+18x+9?