x^2 + 10x + 18 = 0

Question

x^2 + 10x + 18 = 0

anonymous · Answer

use the following formula:$$x=(-b \pm \sqrt{b ^{2}-4ac})/2a$$

anonymous · Answer

Im still confused.

jim_thompson5910 · Answer

x^2 + 10x + 18 = 0


x=(-b+-sqrt(b^2-4ac))/2a



x=(-10+-sqrt(10^2-4(1)(18)))/2



x=(-10+-sqrt(28))/2



x=(-10+-2sqrt(7))/2



x=-5+-sqrt(7)



So the solutions are x=-5+sqrt(7) or x=-5-sqrt(7)

anonymous · Answer

...explain how did you do that? i don't get your work.

jim_thompson5910 · Answer

I'm using the quadratic formula and I plugged in a=1, b=10, and c=18

jim_thompson5910 · Answer

after that I simplified as much as I could

anonymous · Answer

oh

anonymous · Answer

just factor it out or you could use the quadratic formula which is $$x= -b+ or -\sqrt{b ^{2}-4ac}\div2a$$

anonymous · Answer

so 
a=1 ( I got this from the one in (1)x^2) 
b=10 (I got that from the ten in 10x) 
 and c=18 (which i got from the 18 in the equation)
and basically you just plug it in and get your answer (simplying has to be done can do it with a calculator)

anonymous · Answer

just to be clear it isn't or its an and ---i.e. you need to use both the postive and negative of the square root to get the answer! :) so there would be 2 equations ( i just wrote it as one equation)

anonymous · Answer

hope that helped! :D

anonymous · Answer

That was perfect! Thank you!