Question

Can someone explain to me on how to solve a quadratic equation please :)

Answer 1

There are a few ways to do it

Graphically, completing the square, the quadratic formula, factoring etc... just depends one what it looks like :)

Answer 2

Did you have an example you wanted to work through?

Answer 3

do you have a specific equation to work through?

Answer 4

(2x – 1)(x + 7) = 0

Answer 5

Ahh, so these are easier that you might guess

\[\large (2x - 1)(x + 7) = 0\]

Now, you would agree that anything times 0 = 0 right?

Answer 6

yes

Answer 7

Good, then as you can see

\[\large (2x - 1)\times (x + 7) = 0\]

Shows us that we can have 2 ways this would equal 0

First way: If (2x - 1) = 0 because if that is true...it doesn't matter what the second parenthesis equate to...it would be multiplied by 0 anyways

Second way: If (x + 7) = 0 ...same thing here..if this part is 0...it wouldn't matter what the other part is

Answer 8

So all we need to do...is

First: Solve \(\large 2x - 1 = 0\) for 'x'

Then Second: Solve \(\large x + 7 = 0\) for 'x'

Answer 9

2x+1? & x-7?

Answer 10

Not quite

Lets work with the first equation

\[\large 2x - 1 = 0\)

What number can i replace 'x' with there...that would make the equation true?
In other words, "2 times WHAT NUMBER...minus 1..equals 0?

Answer 11

Oops, messed up that latex

\[\large 2x - 1 = 0\] Sorry about that

Answer 12

2?

Answer 13

Nope...if I plug in 2 into that equation for 'x'

\[\large 2(2) - 1 = 0\]
\[\large 4 - 1 = 0\]
\[\large 3 = 0\]

That is untrue

Answer 14

2x−1=0? x+7=0?

Answer 15

those are the equations, yes
but solve for x on each one

2x-1= 0
+1=+1
2x = 1
divide by two on both sides
x= 1/2

Answer 16

x+7= 0
-7 +7
x = 7

so x = 1/2 and 7