Simplifying equations ???? Please help !!?

1. 1/2h(a+b) = 1/(2ha + 2hb)....If you meant (1/2h)(a+b), it's (a + b)/2h

2. 5{-2+3[4-2(3+5)]} = 5{-2+3[4-2(8)]} = 5{-2+3[4-16]} = (5)( 38) = -190

3. [18(x-2)+9x]- {7[3(2y-5)- 8y+7)]+9} = 27x - 36 - {7[6y - 15 - 8y+7]+9} =

27x - 36 - {7[-2y - 8]+9} =27x - 36 - (-14y - 47) = 27x + 14y + 47

4. -3[9(x-4)+5x] - 8{3[5(3y+4)] - 12} = -3[14x - 36] - 8{3[15y + 20] -12} =

-42x + 108 - 8(45y + 48) = - 42x - 360y - 276

Nice work with the parentheses, brackets and braces! Please check what I have done above to find any mistakes.

1. 1/2h(a + b) is 1/2ah + 1/2bh.

2. 5{- 2 + 3[4 - 2(3 + 5)]} =

5{- 2 + 3[4 - 2(8)]} =

5{- 2 + 3[4 - 16]} =

5{- 2 + 3[- 12]} =

5{- 2 - 36} =

5(- 38) =

- 190.

3. [18(x - 2) + 9x] - {7[3(2y - 5) - 8y + 7)] + 9} =

[18(x - 2) + 9x] - {7[6y - 15 - 8y + 7] + 9} =

[18x - 36 + 9x] - {7[- 2y - 8] + 9} =

[27x - 36] - {- 14y - 56 + 9} =

27x - 36 + 14y + 56 - 9 =

27x + 14y + 56 - 45 =

27x + 14y + 11.

4. - 3[9(x - 4) + 5x] - 8{3[5(3y + 4)] - 12} =

- 3[9(x - 4) + 5x] - 8{3[15y + 12] - 12} =

- 3[9x - 36 + 5x] - 8{45y + 36 - 12} =

- 3(14x - 36) - 8(45y + 24) =

- 42x + 108 - 360y - 192 =

- 42x - 360y - 84

or

42x + 360y + 84.

You solve the equations and simplify the expressions now in this case we are doing the latter:

4) -3[9(x-4)+5x] - 8 {3[5(3y+4)] - 12}

= -3[9x - 36 +5x] - 8{3[15y + 20)] - 12}

= -3[14x - 36] - 8{45y + 60 - 12}

= -42x + 108 - 8(45y + 48)

= -42x + 108 - 360y - 384

= -42x - 360y -276

my advise to you try use the MDAS in question #2