Question

x2 - 3x = 4 (the 2 is smal)

Answer 1

x^2 - 3x - 4 = 0

what two numbers added together give you -3 and multiply to give you -4?

Answer 2

A?

Answer 3

LOL

Answer 4

A) 1 4
B) 1 -4
C) -1 4
D) -1 -4

Answer 5

Just use wolfram alpha if you are lazy

Answer 6

i'm not giving you anymore answers if you dont want to learn

Answer 7

i wanna learn just not too good at this lol :)

Answer 8

\[(x-4)(x+1)=0\]

Answer 9

well stop guessing and try and understand

Answer 10

what two numbers can i add together to give me -3

Answer 11

1+2

Answer 12

no that will give you +3 not -3

Answer 13

-4 + ? BIG CLUE

Answer 14

1-2?

Answer 15

that will give you -1

Answer 16

1+2-6?

Answer 17

i said two numbers

Answer 18

not three

Answer 19

0-3?

Answer 20

try taking a look at where i said BIG CLUE !

Answer 21

good your getting there

Answer 22

that would give you -3 but we need to find two numbers that give you -3 and the same two numbers need to multiply to give you -4

Answer 23

plz i only have 10 minutes left

Answer 24

its touching if you want to learn you will make more time

Answer 25

plz i want to learn but just dont have time right now

Answer 26

ok so you have x2 - 3x = 4
the first thing you want to do is equal this to zero, we can do that by subtracting 4
x^2-3x-4=0
Now, like what that person said, what can you multiply to get -4, and add to get -3?
now let's guess and check. 1 * 4 = 4, but 1 + 4 = 5, ew that won't work
hmm. 1 * -4 = -4, and 1 - 4 = -3
that works!
now we use these two numbers, 1 and -4 and plug it back into the original equation (take the -3x away)
x^2+1x-4x-4
basically what we did is split the -3 apart, because you see, 1x-4x equals -3x so it's basically the same thing, but the point of doing this is that you can factor by grouping.
so lets group the first two terms, x^2 and 1x, what two numbers, or variables, go into both of these? well, x does.
x
Now what's x divided by x^2? that's just x
x ( x
now what's x divided by 1x? 1.
x ( x +1 )
you know this is correct when you use the distributive propetry and get what you use to have
now, let's factor the other two terms, -4x and -4
these look like they both go into -4
-4
now, -4x divided by 4? just x.
-4 ( x
-4 divided by -4? 1.
-4 (x+1)
Now, lets bring it all together. the numbers in the parentheses should be the same (you got x+1 in both, so it's right.
(x+1) now let's bring over the numbers that aren't in parentheses x and -4 just put those in parentheses like (x-4)
the factored version is
(x+1)(x-4)
now, we have to equal both of these to zero and solve like a regular algebra problem to get your two solutions
x+1=0
subtract 1 from both sides
x=-1
do the same thing to the other one
x-4=0
add 4 to both sides
x=4
those are your two solutions x=-1 and x=4