How long does it take the giraffe to weigh 85 kg?

[kenewbie]

No, that's not what he is talking about.

happyg1, you don't have to set an expression to 0 to solve an equation. Here, of course, you could subtract 340 from both sides to get x²- 4t- 68= 0 and try to factor. However, I don't think it will be so easy to factor this.

My favored way of solving x²-4t+ 272=340 would be to subtract 272 from both sides: x²- 4t= 68 and then complete the square.

Can you spell out how to go from there? I've only been thought how to solve for zero, if there is a neat way of doing it for any number I'd like to learn it :)

My approach would be (seeing as it is not a complete square):

x² -4t -68 = 0

x = -(-4) +- sqrt( (-4)² - 4 * (-68) ) / 2

x ~= ( 4 +- 16.9 ) / 2

x ~= 10.45 & -6.45

Ah wait, you talk about completing the square. Do you mean like this?

x²- 4t = 68

x²- 4t + 4 = 68 + 4

(x-2)² = 72

x - 2 ~= +-8.5

x ~= 10.5 & -6.5

If so, I must say I prefer the first. catch-all plug and chug algorithms are neat :)

I need to learn latex.

k

 

[HallsofIvy]

If so, I must say I prefer the first. catch-all plug and chug algorithms are neat :)

I need to learn latex.

k

Of course. No thinking required!