geno3141

Let "a number" become x.

"decreased"  means  subtract

"sum of two times a number and 12"  becomes 2x + 12

x - (2x + 12)

20 - 3x  =  11                         Subtract 20:

    - 3x  =  -9                           Divide by -3:

        x  =  3

Let  x  be the first integer.

      x + 2 will be the other integer.

6(x)  =  3(x + 2)

6x  =  3x + 6

3x  =  6

x  =  2   and  x+ 2  =  4

The calculator at this site will give you the correct answer ...

(3 x 4 x 5) - 3  =  57

1 3/4 + 4 3/8

Rewrite both of the common fractions into fractions with a common denominator. Since the denominators are 4 and 8, the common denominator is 8:

1 6/8 + 4 3/8  = 5 9/8  =  5 + 1 1/8  =  6 1/8

I did this rather quickly; if you have questions about any of the steps, please ask.

On this calculator, hit (2nd) then (tan -- which becomes tan^-1) then enter the tan; it's answer will be the angle.

What is the question?

To divide by a fraction, multiply by its reciprocal:

3 ± ½  =  3 x 2/1  =  3 x 2  =  6

V  =  (1/3)·π·r²·h                     First, multiply both sides by 3:

3V  =  π·r²·h                            Now, divide by π·h 

3V / (π·h)  =  r²                       Finally, take the square root of both sides:

±√[ 3V / (π·h) ]  =  r²              If you are in algebra, you need the ±; if you are in geometry, you probably                                                      don't (usaully, you don't have negative radii).