SOLUTION: Solve using the quadratic formula and round your answers to the nearest tenth: 3x^2+4x-2=0 I am so confused and don't even know where to start! Help!

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Solve using the quadratic formula and round your answers to the nearest tenth: 3x^2+4x-2=0 I am so confused and don't even know where to start! Help!      Log On


   

Question 380798: Solve using the quadratic formula and round your answers to the nearest tenth: 3x^2+4x-2=0
I am so confused and don't even know where to start! Help!
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Solve using the quadratic formula and round your answers to the nearest tenth: 3x^2 + 4x - 2 = 0
:
Here it is step-by-step
the quadratic formula:
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
:
The equation is in the form: ax^2 + bx + c = 0;therefore:
a=3; b=4; c=-2
:
Replace these letters in the formula and you have:
x+=+%28-4+%2B-+sqrt%284%5E2-4%2A3%2A-2+%29%29%2F%282%2A3%29+
Now just do the math
x+=+%28-4+%2B-+sqrt%2816-%28-24%29+%29%29%2F6+
Remember minus a minus is a plus
x+=+%28-4+%2B-+sqrt%2816%2B24+%29%29%2F6+
x+=+%28-4+%2B-+sqrt%2840+%29%29%2F6+
Find the square root of 40, there will be two solutions
x+=+%28-4+%2B+6.32%29%2F6+
x = 2.32%2F6
x = .3867 ~ .4
and
x+=+%28-4+-+6.32%29%2F6+
x = -10.32%2F6
x = -1.72 ~ 1.7
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Two solutions: x = .4, x= -1.7
:
:
It's easy to make a math mistake, so it is a good idea to check your
solutions in the original equation. Replace x with .4
3(.4^2) + 4(.4) - 2 = 0
3(.16) + 1.6 - 2 = 0
.48 + 1.6 - 2 = 0
.08 ~ 0, not exact because we rounded off but close enough to check our answer
;
Check it with x=-1.7
3(-1.7^2) + 4(-1.7 - 2 = 0
3(2.89) - 6.8 - 2 = 0
8.67 - 6.8 - 2 = 0
.13 ~ 0, also close
:
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Learn this completely, print it out and study it, it will make life much
easier in algebra class. Like giving yourself a lasting Christmas present!
Best regards, Carl