Answer:
1. 27x+18  =  x+x+x+x+x......+x  + 18
You sum "x" 27 times.
2. [tex](36,\infty)[/tex]
3. [tex]285/2 = 142.4[/tex]
4. 2*(12 Â 1/3 )*(8 Â 1/2) Â + 2*(12 Â 1/3 )*(6 Â 3/4)+2*(6 Â 3/4 )*(8 Â 1/2)
Step-by-step explanation:
1. Remember that multiplication is a simplification of the sum, so, when you say for example, 4*3, that actually means 3+3+3+3, similarly, when you say, 27x, that means x+x+x...+x  27 times.
2. From the image you can see that Â
The 36 is NOT taken, and then you go all the way to infinity, therefore we say [tex](36,\infty)[/tex]. Â Suppose that 36 was taken, then we would say [tex][36,\infty)[/tex].
3. From the attached photo
you can see that we can compute first the area of the rectangle with length = 15 and height = 7, and also note that at the top a triangle with base 15 and height 5 is formed, so the area of the whole figure would be the area of the rectangle at the bottom plus the area of the triangle on top. That would be 7*15+(15*5)/2 = 285/2
4. Remember that in general the formula for surface area would be
                       [tex]2lw +2lh+2wh[/tex]
Where  l = length  ,  w = wide,  h = height.  In this case  l = 12  1/3  , w = 8  1/2  and h =  6  3/4
