how many solutions are there for 5x^2+7x-4=0? a) 0 b) 1 c) 2 d) 3

Question

anonymous · Answer

have you tried to solve it ? :)

anonymous · Answer

well i'm in the process. ;)

anonymous · Answer

what did you get? :)
you have 3 cases   
$$\LARGE b^2-4ac>0$$-Two solutions 

$$\LARGE b^2-4ac=0$$-One solution 

$$\LARGE b^2-4ac<0$$-No solution...

(Eliminate option "d" now) .. ;)

anonymous · Answer

$$\LARGE \sqrt{b^2-4ac}=\sqrt{7^2-4\cdot 5\cdot (-4)}=...?$$

anonymous · Answer

$$\LARGE \sqrt{49-20\cdot (-4)}=\sqrt{49+80}=... $$
because 
$$\LARGE (-)\cdot (-)=(+)$$
and 49+80=129
so
$$\LARGE \Delta>0$$----- Two solutions...
answer is  "C"

anonymous · Answer

omg i was halfway right. ugh, im so proud. :') thanks. lol, you should be my tutor.

anonymous · Answer

lol, Glad to help. I'm sure you already have a tutor (not me) , your professor . Good Luck!

anonymous · Answer

lol, she sucks. but thanks anyways. :p