solving quadratic equations GRAPHICALLY

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dcunited11

New member
Joined
Feb 14, 2005
Messages
15
ok, whenever i type in these 2 problems, i get messed up:

1. 3x^2 + 4x + 10 = 0

when i put this equation into the y= screen on the calc, there is a graph, but it doesn't cross the x-axis. does that mean there is no answer? or is the answer zero, or something like that?

2. .5x^2 -.7x + 1.5 =0

this one does the same as the above

ALSO, to find teh answers graphically, do i press 2nd calc, then zero? i do that, but i can't seem to get an answer.

THANKS!!!
 
dcunited11 said:
ok, whenever i type in these 2 problems, i get messed up:

1. 3x^2 + 4x + 10 = 0

when i put this equation into the y= screen on the calc, there is a graph, but it doesn't cross the x-axis. does that mean there is no answer? or is the answer zero, or something like that?

2. .5x^2 -.7x + 1.5 =0

this one does the same as the above

ALSO, to find teh answers graphically, do i press 2nd calc, then zero? i do that, but i can't seem to get an answer.

THANKS!!!
Click to expand...
1. You got it. No solutions in the Real Numbers. There ARE two solutions, as the Quadratic Formula reveals, but you can wander though that and see for yourself that the two solutions are Complex numbers. You're calculator can't graph that.

2. Same problem.

Note: For a*x^2 + b*x + c = 0, x = -b/2a is always the x=value for the minimum or maximum value.
 
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