like maybe
3 x^2 -18 x + 45 = 0 ?
or
x^2 - 6 x + 15 = 0
https://www.mathsisfun.com/quadratic-equation-solver.html
Solve 18x=45+3x^2
4 answers
3x²+45=18x
Reduce by 3
x²-6x+15=0
Just from here
a=1 b=-6 c=15
Evaluate into the quadratic formula
x=[-b±√(b²-4ac)]/2
Reduce by 3
x²-6x+15=0
Just from here
a=1 b=-6 c=15
Evaluate into the quadratic formula
x=[-b±√(b²-4ac)]/2
I bet you have a typo because I suspect you have not covered complex roots.
Isaac — Please do not use tutors' names in the space for your name. Thanks.