+4 Is there a way to define a variable to use an equation? E.x.: 3x^2-2x+5=y, and I want to assign x a value without changing it out. Is it possible?
+118704 Welcome to web2.0calc forum Catboy13
Umm - Interesting question. 
\begin{array}{rll} 3x^2-2x+5&=&y\\\\ 3x^2-2x&=&y-5\\\\ x^2-\frac{2}{3}x&=&\frac{y-5}{3}\\\\ x^2-\frac{2}{3}x+\left(\frac{2}{6}\right)^2&=&\frac{y-5}{3}+\left(\frac{2}{6}\right)^2\\\\ x^2-\frac{2}{3}x+\left(\frac{1}{3}\right)^2&=&\frac{y-5}{3}+\left(\frac{1}{3}\right)^2\\\\ x^2-\frac{2}{3}x+\left(\frac{1}{3}\right)^2&=&\frac{3(y-5)}{9}+\frac{1}{9}\\\\ \left(x-\frac{1}{3}\right)^2&=&\frac{3y-15+1}{9}\\\\ \left(x-\frac{1}{3}\right)^2&=&\frac{3y-14}{9}\\\\ x-\frac{1}{3}&=&\pm\sqrt{\frac{3y-14}{9}}\\\\ x&=&\frac{1}{3}\pm\sqrt{\frac{3y-14}{9}}\\\\ x&=&\frac{1\pm\sqrt{3y-14}}{3}}\\ \end{array}
If you first define a function f as
f(x)=3×x2−2×x+5
then for any particular x the function f(x) has a value and you can write things such as
f(2) + f(0) - 4 = 14
+118704 Welcome to web2.0calc forum Catboy13
Umm - Interesting question.
\begin{array}{rll} 3x^2-2x+5&=&y\\\\ 3x^2-2x&=&y-5\\\\ x^2-\frac{2}{3}x&=&\frac{y-5}{3}\\\\ x^2-\frac{2}{3}x+\left(\frac{2}{6}\right)^2&=&\frac{y-5}{3}+\left(\frac{2}{6}\right)^2\\\\ x^2-\frac{2}{3}x+\left(\frac{1}{3}\right)^2&=&\frac{y-5}{3}+\left(\frac{1}{3}\right)^2\\\\ x^2-\frac{2}{3}x+\left(\frac{1}{3}\right)^2&=&\frac{3(y-5)}{9}+\frac{1}{9}\\\\ \left(x-\frac{1}{3}\right)^2&=&\frac{3y-15+1}{9}\\\\ \left(x-\frac{1}{3}\right)^2&=&\frac{3y-14}{9}\\\\ x-\frac{1}{3}&=&\pm\sqrt{\frac{3y-14}{9}}\\\\ x&=&\frac{1}{3}\pm\sqrt{\frac{3y-14}{9}}\\\\ x&=&\frac{1\pm\sqrt{3y-14}}{3}}\\ \end{array}
