SOLUTION: {{{ 5x^2+18=3 }}} i dont understand the whole i thing

Question 238277:
i dont understand the whole i thing
Found 2 solutions by checkley77, College Student:
Answer by checkley77(12844) (Show Source): You can put this solution on YOUR website!

5X^=3-18
5X^2=-15
X^2=-15/5
X^2=-3
X=SQRT-3
X=1.732i ANS.

Answer by College Student(505) (Show Source): You can put this solution on YOUR website!
Ok. If we try to solve for x, this is what we would get:

...same as... (an imaginary answer)
.
Now, we know that if we multiply two negative numbers, the result will always be a positive number. But in this problem, we see that a number raised to the second power (same as having a number multiplied by itself) should equal -3. This directly contradicts the rule. So, Rafael Bombelli (back in 1572) invented the imaginary number we know as "i" to be able to work out these problems.
.
"i" =
.
Suppose the answer would have been ... since we know the square root of 9 is 3, we could then say ...same as...
But in your problem, leave it as .
.
I hope this explanation helped. :)
RELATED QUESTIONS
(x/x+1) - (2/x-1) - 1 please explain/show this to me... i tried doing it and again,... (answered by edjones)
i dont get the whole thing of fractional exponents can someone please... (answered by drj)
i dont get the whole thing of fractional exponents can someone please... (answered by drj)
i dont understand this problem 5x =... (answered by Maths68)
solve the compound inequalities 6>-3x+5 or 9<= -5x+3 I dont understand this... (answered by bucky)
i dont understand how to complete the square on y=.5x^2-3x+19/2. i also have to graph... (answered by ankor@dixie-net.com,josmiceli)
can you explain the whole quadratic unit because i really dont understand it... (answered by stanbon)
I dont get how the whole solving system of equations by substitution and elimination... (answered by Earlsdon)
2/3 m +8=20 i dont understand how m=18 (answered by rfer)