CPhill

Another way :

[ 12 + 7 - 2 ] * 3   =

[ 19 - 2 ] * 3   =

17 * 3   =

51

This is undefined when x - 5   =   0.....thius   w = 5 makes the rational function undefined

1.555555......   = 1+ 5/9    =  14/9

 [ 5x+2 ] / [ x^2+9x+20]

This is only undefined if  x^2 + 9x + 20   = 0

So,  factoring, we have

(x + 5) ( x + 4) = 0        and setting each factor to 0,  the function is undefined when x = -4   or x = -5

[x-6] /[x^2+2]

Note that this is undefined only if the denominator = 0  .........but

x^2 +  2     can never equal 0....thus, the denominator  is never 0......so nothing makes this undefined

1333 / 5280  = about . 25 mi   [ 1/4 of a mile]

75+15x>140     subtract 75 from each side

15x > 65         divide both sides by 15

x> 65/15

x > 13 / 3

20≥−3.2(c−4.3)       divide both sides by  -3.2   and reverse the inequality sign

20/ - 3.2  < c - 4.3    add 4.3 to both sides

20/ -3.2 + 4.3 <  c

[-20] / [ 32/10] + 43/10 < c

[-20 * 10] / 32 + 43/10  <  c

-200/32 + 43/10 <  c

-25/4 + 43/10 <  c

[-250 + 172] / 40 <  c

-78/40 <  c

-39 / 20 < c

There is no solution to this......

6x + 1   = 6x - 8       subtract 6x from both sides

1 =  - 8        but this is impossible....!!!!....so.....no solution exists  !!!

What model????