$y^{\text{'}}=42(y-4x9{)}^{\frac{1}{2}},$ with $y(0)=0$

by using an appropriate substitution.

For $x_1=7,$ find $y(x_1).$

Include at least $3$ decimal places in eath step in your calculation. Use $=3\mathrm{.}14159$ and $e=2\mathrm{.}71828.$