determine the number and type of solutions for x^2 + 9x +7=0

Question

anonymous · Answer

well it's a quadratic so there will be two solutions.

You can tell because of the

$$x^2$$

anonymous · Answer

2 irrational, rational, or complex?

anonymous · Answer

You can use the quadratic formula to solve for x

\begin{array}{*{20}c} {x = \frac{{ - b \pm \sqrt {b^2 - 4ac} }}{{2a}}} & {{m{when}}} & {ax^2 + bx + c = 0} \ \end{array}

anonymous · Answer

Hmm well you can try solving it see what type of values you will get if it's hard to tell by looking at it.

cwrw238 · Answer

discriminant = 81 - 28 = 53
so thers 2 rational roots

anonymous · Answer

thank you!

cwrw238 · Answer

yw

anonymous · Answer

How did you find the discriminant?

cwrw238 · Answer

b^2 - 4ac 
here b = 9,a=1 and c = 7
so its

9^2 - 4*1* 7

anonymous · Answer

that answer was wrong..btw o-o

anonymous · Answer

Right if the discriminant is higher than zero then we know that it can't be a complex number.


Btw if the answer is wrong there is only one other possible solution.

cwrw238 · Answer

if D > 0  then there are 2 roots - oh right they are not necessarily rational

cwrw238 · Answer

in fact since  D = sqrt53 there are both irrational

cwrw238 · Answer

i should have said ( 2 posts ago) D>0 means there are 2 REAL roots which could be rational or irrational