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I copied down 2 problems I didn't understand on my math test that I wanted to the see the answers of.

1.) Solve by the quadratic formula.

x² - 12x + 33 = 0


2.) C = 28t² + 145t + 4235 --- By what year will the total number of cars be 39,000.

A: 2050
B: 2000
C: 1986
D: 1975

2007-05-02 08:21:22 · 5 answers · asked by Drick 3 in Science & Mathematics Mathematics

For the second problem.... the starting year is 1969.

2007-05-03 00:01:43 · update #1

5 answers

1) a = 1, b = -12, c = 33

x = [12 +/- sqrt(144 - 4(1)(33))] / (2(1))

x = [12 +/- sqrt(12)] / 2

x = [12 +/- sqrt(4)*sqrt(3)] / 2

x = [12 +/- 2sqrt(3)] / 2

x = 6 +/- sqrt(3)

2. No real solution exists...maybe you missed a negative sign somewhere? If the 4235 should be negative, then the solution is about x = 10. If the 28 should be negative, then the solution is about x = 15. You also didn't give what year was considered the "zero year".

2007-05-02 08:25:19 · answer #1 · answered by Anonymous · 0 0

1. use the quadratic equation 12+/- sqrt of (144- 4*33) all over 2

so simplify to 12+/- sqrt(12) all over 2

12+/- 2sqrt 3 all over 2

so the two answers are 6+ sqrt(3) and 6- sqrt(3)

2. you have not really given enough information but this is how you solve it:

39000= 28t^2+145t+4235


28t^2+145t-34765=0 use quadratic equation (to much to type but you come out with 33 years) so it will take 33 years don't know what year you started from

2007-05-02 08:32:35 · answer #2 · answered by sharkey 4 · 0 0

1. x² - 12x + 33 = 0
to solve this you need to use the formula:
x = {-b (+or-) squareroot(b^2 - 4ac)} / 2a

where a = the coefficient of x^2 which in this case is 1
b = the coefficient of x which in this case is -12
c = the constant which in this case is 33

So x = {12 (+or-) squareroot(144 - 132)} / 2
= {12 (+or-) squareroot 12} / 2
So x = {12 + squareroot 12} / 2
or x = {12 - squareroot 12} / 2

2007-05-02 08:30:28 · answer #3 · answered by Anonymous · 0 0

x² - 12x + 33 = 0

x1=6+ 2sqrt(3)

x2=6- 2sqrt(3)


28t² + 145t + 4235 -39000=0
t=?

2007-05-02 08:28:13 · answer #4 · answered by iyiogrenci 6 · 0 0

x² - 12x + 33 = 0
x=(1/2[12+or-sqrt(144-132)]=(1/2[12+ or -sqrt(12)]=(1/2[12+Or-2.sqrt(3)]=6+ or - sqrt(3). answer

2007-05-02 08:32:57 · answer #5 · answered by Anonymous · 0 0

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