Question

i really don't understand these..2x^2+5x-3 i know some of you helped but i don't understand

Answer 1

Again, this is a quadratic expression.

Answer 2

Do you NOW wanna know how to do these?

Answer 3

yes...i have to do this by tonight so plz help

Answer 4

All quadratic expressions after grouping are expressed as \(\Large \color{purple}{\rightarrow (zx + a)(x + b) }\)

Answer 5

Now, let's see it in detail.

Answer 6

Also, quadratic expressions are in the form --> ax^2 + bx + c

Answer 7

What do you want to do with these?

Answer 8

can you explain step by step how to do them? i have alot more like these..

Answer 9

To factor, ac must be equal to the numerical coefficient of the middle term.

Answer 10

http://www.youtube.com/watch?v=eF6zYNzlZKQ This guy is magical.

Answer 11

2x^2+5x-3


2x^2-x+6x-3


(2x^2-x)+(6x-3)


x(2x-1)+(6x-3)


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


(x+3)(2x-1)



So 2x^2+5x-3 completely factors to (x+3)(2x-1)

Answer 12

Notice that 2*(-3) = -6. Two numbers that multiply to -6 and add to 5 are -1 and 6. So we break up 5x into -x+6x. From there, you factor by grouping.

Answer 13

thanks

Answer 14

A little more on factoring quadratics:

I learned the "bust the b" technique.

4 x² -1x + 18

a = 4 and c = 18 and b = -1.

The task on "bust the b" is to find numbers that mutiply to a*c AND add to b.

In this case, numbers that multiply to 4*18 and add to -1.

14 * 18 breaks aparts into the product of prime factors : 2*2*2*3*3

Look at those five factor of 14 * 18 and try to put them in the form of 2 numbers that differ by -1.

2*2*2 and 3*3 appear to differ by 1. That would be 8 and 9.

"b" has been "busted into 8 and - 9 whose sum is -1 which equals "b" in this problem.

4x - x+ 18 = 4 x² + 8 x - 9 x - 1.

The "b" has been busted.

Factoring by grouping comes next.

4 x² + 8 x - 9 x - 18 =

4x ( x + 2) - 9 ( x + 2 ) = --> On this step, (x + 2) is the common factor of the expression.

[ (x + 2) ] ( 4x - 9 ) =

( x + 2 ) ( 4x - 9)