Bosco

   how do you find the axis of symmetry from y = (x-9)(x+5)?     

   You can tell from the factors that the parabola crosses the x-axis at +9 and –5.     

   The axis of symmetry is the vertical line halfway between these two crossings.     

   The axis of symmetry, i.e., the line halfway between (–5,0) and (+9,0), is x = 2.     

   _.     

   square root of 49     

   sqrt(49) = + 7      That's pronounced "plus or minus seven".     

   Everybody knows the square root of 49 is 7.  That part is easy.     

   Half of them forget that negative 7 is also the square root of 49.     

   _.     

   what is 123456789x8+9=     

   (123456789 x 8) + 9  =     987,654,321     

   123456789 x (8 + 9)  =  2,098,765,413     

   By the products I now know which one you meant.  Neat.     

   Here's one for you.  Notice that you have to omit the 8.     

   12345679 x (2 x 9)  =  222,222,222     

   12345679 x (3 x 9)  =  333,333,333     

   12345679 x (5 x 9)  =  555,555,555     

   12345679 x (7 x 9)  =  777,777,777     

   Try it with the others:  1x9, 4x9, 6x9, 8x9, 9x9     

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whats 10*10^23 expressed as expression?     

           10 • 10²³  =  10²⁴     

_.     

   Lionel deposited $3,631.23 in a savings account that earns 1.9% simple interest. What will Lionel's account balance be in 8 months?     

   3631.23  x  0.019   =      68.99    interest after twelve months     

       68.99  x  ( ⁸/₁₂ )  =      46.00    interest after eight months     

   3631.23  +  46.00   =  3677.23    interest plus principal after eight months     

_.     

Ann throws a dice 30 times. The chances of getting 1, 2, 3, 4, 5 or 6 are equal.     

a. How big of a chance is there that her next throw will be a 3?     

b. Ann throws the dice another 12 times. How many times is she expected to throw a 3 on these 12 throws?     

a.  1 / 6    Previouse results have no effect on the probability of the next throw.*     

b.  2 / 6     I think the word "expected" is inappropriate.     

                 Instead, say "the probability" of throwing another 3.     

* You might be tempted to say, "Well, that darn three will never come."     

   Alternatively, "Well, the three hasn't come up,  It's due any time now."     

   These fallacious conclusions are one way casinos make their money.     

_.     

   3 and 1 sixth minus 3 fourths plus five sixths     

   3 ¹/₆   –   ³/₄   +   ⁵/₆     

   ¹⁹/₆   –   ³/₄   +   ⁵/₆     

   need common denominator . . .  12 will do     

   ³⁸/₁₂  –  ⁹/₁₂  +  ¹⁰/₁₂   =   ³⁹/₁₂     

                                        =   3 ³/₁₂     

                                        =   3 ¹/₄     

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