Question

If √6b+4=20, then what is the value of b

Answer 1

$D:6b+4\geq0\to b\geq-\dfrac{2}{3}\\\\\sqrt{6b+4}=20\ \ \ |^2\\\\(\sqrt{6b+4})^2=20^2\\\\|6b+4|=400\to 6b+4=400\ \vee\ 6b+4=-400\ \ |-4\\\\6b=396\ \vee\ 6c=-404\ \ \ |:6\\\\b=66\in D\ \vee\ b=-67\dfrac{2}{3}\notin D$

$Answer:\ b=66$