CPhill

√58 ≈  7.616

1 1/8   = 9/8

So

(9/8) * (4/5)  =

(4/8) * (9/5)  =

(1/2) * (9/5)  =

9 / 10

Notice the difference :

(-9)^2   = (-9) * (-9)   = 81

BUT.....

-9^2   actually means   -1*9^2   =  -1 * 9  * 9   = -81

Moral of the story......parentheses matter   !!!!!

Edited answer for the third part :

126, 189, 252, 315, 378, 441, 504, 567, 630, 693, 756, 819, 882, 945

For the third one....I also noticed that  189, 819   and  567 and 756 actually have the same digits

So......my answer should have been

[9 * 6  +  3 *3]  / 1000  = 63/1000

Sorry!!!!

Converting 90mph  to ft/sec  =  90mph * [88ft/sec] / [60mph]   = 132 ft/s

So....the ball takes    60ft / 132ft/s  =  about  .45 sec to reach home plate

Thus.....if the runner can travel from 1st to 2nd base in under .45 seconds, he will be safe

tan (3°)  = (2.5) / D    where D is the distance from the bottom of the ramp to the building

Rearrange as

D  = (2.5) / tan(3°)  = about 47.7 feet

10 ( x - 5)  = - 80        divide both sides by 10

x - 5  = - 8                 add 5 to both sides

x = -3

(4x+2)/2=x+8       multiply both sides by 2

4x + 2  =  2(x + 8)    simplify

4x + 2  = 2x + 16      subtract 2x, 2 from each side

2x  = 14      divide both sides by 2

x = 7

sec^2 x cos x + cos x - 2 = 0

(1/cos^2x)*cosx + cosx - 2  = 0

1/cosx + cosx  - 2  = 0       multiply through by cos x

1 + cos^2x - 2cosx  = 0     rearrange

cos^2 x - 2cos^2x + 1  =  0       factor

(cosx -1) (cosx - 1)  = 0     and since the factors are the same, we can solve for just one of them

cosx - 1   = 0      add 1 to both sides

cosx  = 1       so,   x  =    0 ± n*360°  where n is just an integer

Circumference  = 2 * pi * 4   =  8 pi  units

Area = pi (4)^2  = 16 pi units^2