# Math Help - please explain to me how to simplify this equation

1. ## please explain to me how to simplify this equation

please show me how to simplify this equation
(2x+1)(x-3)2 the 2 at the end of the equation is squared

2. Originally Posted by lostone
please show me how to simplify this equation
(2x+1)(x-3)2 the 2 at the end of the equation is squared

$(2x+1)(x-3)^2$

Unless you want to multiply it out.

3. Originally Posted by lostone
please show me how to simplify this equation
(2x+1)(x-3)2 the 2 at the end of the equation is squared

this is simplified, you mean you want to expand

ok, i won't try to confuse you with the shortcut on expanding binomial squares, let's get down and dirty. rewrite the square term as two terms, then work on the sets of brackets two by two. take one term in one set of brackets and multiply everything in the other set of brackets, then take the other term in the first set of brackets and multiply everything in the other set of brackets again

$(2x + 1)(x - 3)^2 = (2x + 1)(x - 3)(x - 3)$

$= (2x + 1)(x^2 - 3x - 3x + 9)$

$= (2x + 1)(x^2 - 6x + 9)$

$= 2x^3 - 12x^2 + 18x + x^2 - 6x + 9$

$= 2x^3 - 11x^2 + 12x + 9$

got it?

4. But isn't bad remember it $(a-b)^2=a^2-2ab+b^2$

Greetings

5. Originally Posted by Krizalid
But isn't bad remember it $(a-b)^2=a^2-2ab+b^2$

Greetings
that's true, that's "the shortcut" i was talking about. in fact, it is more general than that:

$(a \pm b)^2 = a^2 \pm 2ab + b^2$

however, in my experience, most students are intimidated by such formulas and actually prefer to do it the long way. i figured if lostone was interested in the formula he/she would ask, "so what's the shortcut?" but lostone seemed pleased, so i just didn't say anything. besides, knowing the long way helped to simplify the other part when you had the binomial times the trinomial