1. Solve 5x2 = –45x 1. Solve 5x2 = –45x @Mathematics

Question

1.	Solve 5x2 = –45x 1.	Solve 5x2 = –45x @Mathematics

anonymous · Answer

x^2 = -45x / 5
x = -45/5
x=-9

anonymous · Answer

when you divide by x, you lose a solution.   The original equation is quadratic, so there are two solutions.  One of them can be obtained in the manner above, but you lost the other.

So solve like this instead, so you get both:$$5x^2=-45x\iff5x^2+45x=0\iff 5x(x+9)=0\iff x=0,x=-9 $$

anonymous · Answer

either is good answer

anonymous · Answer

right, both will solve the problem.  sometimes the question will want both solutions though. just a heads up :)

anonymous · Answer

just in case do i add x = 0 to the answer ?

anonymous · Answer

they are both viable solutions so supplying one or the other wont make you wrong

anonymous · Answer

ok