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Maths Help Needed :(

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Tohru Kyo Sohma:

--- Quote from: astarmathsandphysics on August 23, 2012, 07:48:08 pm ---D then C for the first 2.
For the third I make it A using the quadratic formula.

--- End quote ---
Quadratic formula
x= (-b+- root of b^2-4ac)/2a
x= -6+- root of 36+24 / 2*2
x=-3 +- root of 60 /2
root of 60 is also 2 root of 15

how A then?

astarmathsandphysics:
sqrt(60)=sqrt(4*15)=sqrt(4)*sqrt(15)=2 sqrt(15)

astarmathsandphysics:
(-6+-sqrt(60))/4 =(-6+-2sqrt(15))/4=(-3+-sqrt(15))/2

Tohru Kyo Sohma:

--- Quote from: astarmathsandphysics on August 24, 2012, 06:06:44 pm ---(-6+-sqrt(60))/4 =(-6+-2sqrt(15))/4=(-3+-sqrt(15))/2

--- End quote ---
wait how did the 2 disappear from there!

Tohru Kyo Sohma:
1.Using a phone card to make a long distance phone calls costs a flat fee of $0.85 plus $0.19 per minute starting with the first minute. What id the total cost a phone call which lasts 8 minutes?
a. $2.37
b. $6.00
c. $8.16
d. $1.52
e. none of the above

I THINK ITS A

2. A survey of 250 residence indicated that 170 owned a TV, 130 owned a DVD and 80 owned both TV and DVD. How many donot own a TV or a DVD?
a. 50
b. 90
c. 30
d. 80
e. none of the above

I THINK ITS C[/b]

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