Question

What is a the positive solution of x^2 - 36 =5x​

Answer 1

x = 9

Explanation:

`x^2-36=5x\qquad\text{subtract}\ 5x\ \text{from bot sides}\\\\x^2-5x-36=0\\\\x^2+4x-9x-36=0\qquad\text{distribute}\\\\x(x+4)-9(x+4)=0\\\\(x+4)(x-9)=0\iff x+4=0\ \vee\ x-9=0\\\\x+4=0\qquad\text{subtract 4 from both sides}\\\\x=-4<0\\\\x-9=0\qquad\text{add 9 to both sides}\\\\x=9>0`