Question #3c005

1 Answer
Aug 11, 2016

There are 2 Real roots

Explanation:

Consider the standard form equation: y=ax^2+bx+cy=ax2+bx+c

Where: x=(-b+-sqrt(b^2-4ac))/(2a)x=b±b24ac2a

Now consider the discriminate: b^2-4ac=10b24ac=10

The fact that this is positive means that the solution for xx belongs to the set of Real Numbers: x in RR

Thus we have (-b)/(2a)+-(sqrt(10))/(2a)

Also sqrt(10)/(2a) !=0 and (-b)/(2a) !=0

Let x_1=(-b)/(2a)+(sqrt(10))/(2a)

Let x_2=(-b)/(2a)-(sqrt(10))/(2a)

Thus x_1-x_2 =cancel(-(b)/(2a))+(sqrt(10))/(2a)cancel(+ (b)/(2a))+(sqrt(10))/(2a)

x_1-x_2" "=" " cancel(2)xxsqrt(10)/(cancel(2)a)

As there is a defined distance between the two points then they do not coincide. Thus there are two separate points.
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Lets try out two equations " "b^2-4ac by making up some numbers.

Suppose we had:" "b^2-4(2)(10) =10
=>b^2=10+80=90" "->" "b=3sqrt(10)

Giving:" "2x^2+3sqrt(10)x+10

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Suppose we had:" "b^2-4(1)(2)=10
=>b^2=10+8" "->" "b=3sqrt(2)

Giving:" "2x^2+3sqrt(2)x+2
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This is how they look on the graph:
Tony B