The general formula of a 2nd degrree polynomial is
ax^2 + bx + c = 0
Rewritting the equation in this form, you get 4x^2 - 13x - 12 = 0
Thus, a = 4, b = -13, c= -12
The quadratic formula is (-b[+-] sqrt(b^2-4ac))/2a
Plugging in the values, you get (13[+-]sqrt(169+192))/8
=(13 [+-] 19)/8
Thus your two answers are (13+19)/8 = 4, (13-19)/8 = -3/4
2006-10-04 17:12:27
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answer #1
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answered by JSAM 5
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4x^2 = 13x + 12
4x^2 - 13x - 12 = 0
the discriminant of the quadratic expression on the left-hand side is b^2 - 4ac = (-13)^2 - 4(4)(-12) = 169 + 16(12) = 361 = (19)^2, which is a perfect square. hence, the quadratic expression is factorable as:
(x - 4)(4x + 3) = 4x^2 - 16x + 3x - 12 = 4x^2 -13x - 12
hence, (x - 4)(4x + 3) = 0.
consequently, either x = 4 or x = -3/4.
for additional information, try looking up "quadratic formula" on the InterNet.
2006-10-05 00:14:00
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answer #2
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answered by JoseABDris 2
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you have to make the equation equal to zero:
0= 4x^2+13x+12
then put it in the quadratic formula. Sorry!
2006-10-05 00:13:18
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answer #3
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answered by Roxy 2
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4x^2=13x+12,it can be written as
4x^2-13x-12=0,now
4x^2-16x+3x-12=0
4x(x-4) +3(x-4)=0
either x-4=0 or 4x+3=0
so two values are
x=4, x= -3/4
2006-10-05 03:04:50
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answer #4
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answered by neeti 2
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"4x^2=13x+12"
4x^2 - (13x+12)=13x+12 - (13x+12)
4x^2-13x-12=0
a=4; b=-13; c=-12
Use the quadratic formula.
-b+/-(sqrt)b^2-4ac/2a
Plug in...
-(-13)+/-(sqrt)-13^2-4(4)(-12) / 2(4)
13+/-(sqrt)169+192 / 8
13+/-(sqrt)361 / 8
The square root of 361 is "19"
So...
13+/-19 / 8
You will have two answers...
13+19/8
=32/8
=4
13-19/8
=-6/8
=-3/4
So your answers are... "4" and "-3/4".
YOU'RE WELCOME IN ADVANCE. IM GLAD TO HELP.
2006-10-05 00:22:14
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answer #5
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answered by ViCKi!™|` 5
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4x^2-13x-12=0
(4x+3)(x-4)=0
2006-10-05 00:44:54
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answer #6
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answered by Helmut 7
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4x^2 = 13x + 12
4x^2 - 13x - 12 = 0
x = (-b ± sqrt(b^2 - 4ac))/(2a)
x = (-(-13) ± sqrt((-13)^2 - 4(4)(-12)))/(2(4))
x = (13 ± sqrt(169 + 192))/8
x = (13 ± sqrt(361))/8
x = (13 ± 19)/8
x = (32/8) or (-6/8)
x = 4 or (-3/4)
2006-10-05 00:13:12
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answer #7
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answered by Sherman81 6
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4x^2-13x-12=0
x= [b +- (b^2 - 4ac)^1/2]/2a
=>
x= 4 , -3/4
2006-10-05 00:12:08
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answer #8
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answered by alwayss_ready 3
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