SOLUTION: i am supposed to solve this equation y=2n^2+2n-24 using the quadratic formula and i dont know how can you help

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: i am supposed to solve this equation y=2n^2+2n-24 using the quadratic formula and i dont know how can you help      Log On


   

Question 960248: i am supposed to solve this equation y=2n^2+2n-24 using the quadratic formula and i dont know how can you help
Found 2 solutions by lwsshak3, josmiceli:
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
y=2n^2+2n-24
solve for n using quadratic formula:
n+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
a=coefficient of n^2 =2
b=coefficient of n=2
c=constant=-24
n+=+%28-2+%2B-+sqrt%28+2%5E2-%284%2A2%2A-24%29%29%29%2F%282%2A2%29+
n+=+%28-2+%2B-+sqrt%28196%29%29%2F%284%29+
n+=+%28-2+%2B-+14%29%2F%284%29+
n=-16/4=-4
or
n=12/4=3

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
+y+=+2n%5E2%2B2n-24+
The quadratic formula for this is:
+n+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
where the form of the equation is:
+y+=+a%2An%5E2+%2B+b%2An+%2B+c+
Compare this with your equation
You can see that:
+a+=+2+
+b+=+2+
+c+=+-24+
Now do the substitutions
Notice the [ +- ] in the middle of the formula
That means you will end up with 2 values for +n+
( most likely )
------------------------------------
+n+=+%28-2+%2B-+sqrt%28+2%5E2-4%2A2%2A%28-24%29+%29%29%2F%282%2A2%29+
+n+=+%28-2+%2B-+sqrt%28+4+%2B+192+%29%29%2F4+
+n+=+%28-2+%2B-+sqrt%28+196+%29%29%2F4+
+n+=+%28-2+%2B+14%29%2F4+
+n+=+12%2F4+
+n+=+3+
--------------
Now use the minus square root
+n+=+-2+-14+%29+%2F+4+
+n+=+-16%2F4+
+n+=+-4+
-------------
Now I can say:
+n+-+3+=+0+
+n+%2B+4+=+0+
and
+%28+n+-+3+%29%2A%28+n+%2B+4+%29+=+0+
+n%5E2+-+3n+%2B+4n+-+12+=+0+
+n%5E2+%2B+n+-+12+=+0+
Multiply both sides by +2+
+2n%5E2+%2B+2n+-+24+=+0+
This is the function that I started with
Here's the plot:
+graph%28+400%2C+400%2C+-10%2C+10%2C+-30%2C+10%2C+2x%5E2+%2B+2x++-+24+%29+
Hope this helps