x（30-x）=63怎么解啊,要具体解的过程,

x（30-x）=63怎么解啊,要具体解的过程,
x（30-x）=63怎么解啊,要具体解的过程,

x（30-x）=63怎么解啊,要具体解的过程,
30x-x²=63
x²-30x=-63
x²-30x+225=-63+225
(x-15)²=162
x-15=±9√2
x=15-9√2,x=15+9√2