Use the Quadratic Formula to solve the equation.

-2x2 - 5x + 5 = 0

Question

Use the Quadratic Formula to solve the equation.

-2x2 - 5x + 5 = 0

hartnn · Answer

Compare your quadratic equation with $ax^2+bx+c=0$
find $$a=...?\b=...?\c=...?\$$ $$ \ \sqrt{b^2-4ac}=...?$$

anonymous · Answer

@hartnn but that is for finding the discriminant. But to solve the equation, you have to use the formula $$-b \pm \sqrt{b^2-4ac}  /2a$$

hartnn · Answer

yes, that is the next step

if you notice, the formula has 
sqrt(b^2 -4ac)
so we better find it before using the formula :)

anonymous · Answer

ok now what?

hartnn · Answer

what values did u get ? 
for a,b,c ?

anonymous · Answer

idk how am i suppose to plug them in? My computer is being dumb saying "math processing error"

hartnn · Answer

-2x^2 - 5x + 5 = 0

compare it with 
ax^2+bx+c =0

anonymous · Answer

so a is -2? b is -5 and c is 5? :)

hartnn · Answer

thats correct!

now calculate 
sqrt (b^2 -4ac) = ...

anonymous · Answer

(-5^2-4(-2*5)) ?

hartnn · Answer

careful with brackets 
$(-5)^2 - 4 (-2)(5) = ... ?$

anonymous · Answer

So its not like that ^^?

hartnn · Answer

oh sorry, i forgot...

(-5)^2 - 4 (-2)(5) = ...

anonymous · Answer

-5^2 = -25 right? so -25 -4 = -29?

hartnn · Answer

b = -5
and b^2 will be (-5)^2 = -5*-5 = +25

anonymous · Answer

oh ...im really bad at this

anonymous · Answer

My answer is suppose to be like a fraction let me show you answer choices \

anonymous · Answer

anonymous · Answer

anonymous · Answer

anonymous · Answer

hartnn · Answer

4 (-2)(5)  = - 40 

+25 - (-40) = +25 + 40 = +65

b^2 -4ac = +65

sqrt(b^2-4ac) = sqrt (65)

anonymous · Answer

So it A or D?

anonymous · Answer

Or is my answer D?

hartnn · Answer

|dw:1403633011590:dw|