Quadratic formula

[spaul]

I have been given this equation to solve (not using the completing the square or the quadratic formula)

3x^2=5

 

[Dr.Peterson]

How about taking a square root?

 

[Steven G]

x^2 is unknown. We know that 3 times it is 5. So what do you multiply 3 by to get 5? Whatever answer you get is what x^2 equals.

 

[pka]

3x^2=5

\(\displaystyle \begin{gathered}
3{x^2} = 5 \\
{x^2} = \frac{5}{3} \\
{x^2} = \frac{{15}}{9} \\
x = \pm \frac{{\sqrt {15} }}{3} \\
\end{gathered}\)

 

[Peter75]

transfers reims
I have been given this equation to solve (not using the completing the square or the quadratic formula)

3x^2=5

so what method should we use ?

 

[pka]

so what method should we use ?

Written in standard form it is \(\displaystyle 3x^2+0\cdot x-5=0\),
So \(\displaystyle a=3,~b=0~\&~c=-5\).
Thus the roots are: \(\displaystyle \dfrac{-b\pm\sqrt{b^2-4ac}}{2a}\)
Now you finish.

 

[Steven G]

\(\displaystyle 3 \cdot WHAT = 5 \)
Whatever that answer is, set x² to that number.