i keep getting the wrong answer for this exercises. mathematicians help me out pls!!?

Question

equation
1) 3 lx+3l -5=10

formula
2) Solve the formula C = 5/9(f-32) for f

3) A= 1/2h (B+b) for h

Answer 1

1) 3 lx+3l -5=10
divide -5 by 10
3 lx+3l=-2
divide 3 by 2
lx+3l= -2/3
x= -2/3 - 3
x= -3 2/3 or -11/3

3lx+3l -5= -10
divide -5 by -10
3lx+3l= 2
lx+3l= 2/3
x= 2/3 -3
x= -7/3

there are 2 answers when there is an absolute value..
final answer: SS{-11/3, -7/3}

2)C= 5/9(f-32) for f
9/5C= F-32
transpose 32
9/5C+32=f

final answer: f= 9/5C+32

3)A= 1/2h (B+b) for h
A/B+b= 1/2h
2A/B+b=h

final answer: h=2A/B+B

Is that a hw? same lessons,,, we just took that up! well, gud luck!

Answer 2

1) 3 |x + 3| - 5 = 10
Add 5 to both sides : 3 |x + 3| = 15
Divide both sides by 3 : |x + 3| = 5
Taking the positive value : x + 3 = 5 gives x = 2
Taking the negative value : -(x + 3) = 5 gives x = -8

2) C = (5 / 9)(F - 32)
Multiply both sides by 9 : 9C = 5(F - 32)
Divide both sides by 5 : 9C / 5 = F - 32
Add 32 to both sides : F = 9C / 5 + 32

3) A = (1 / 2)h(B + b)
Multiply both sides by 2 : 2A = h(B + b)
Divide both sides by (B + b) : h = 2A / (B + b)

Or if it is : A = 1 / [2h(B + b)]
Multiply both sides by 2(B + b) : 2A(B + b) = 1 / h
Take reciprocal of both sides : h = 1 / [2A(B + b)]

Answer 3

1- 3lx+3l -5=10

3lx+3l-5+5 = 10+5
3lx+3l = 15
{3lx+3l}/3 = 15/3
lx+3l = 5
now you get rid of the absolute value by dividing it to tow formulas
1- x+3=5
x+3-3=5-3
x = 2
and
2- -(x+3)=5
-(x+3) * -1=5 * -1
x+3=-5
x+3-3=-5-3
so x = -8

that's for the first one
2- C = 5/9(f-32) ..... multiply both sides by 5
5C= 9(f-32)........ divide both sides over 9
5/9C = (f-32) ....... add 32 to both sides
5/9C + 32 = f

3) A= 1/2h (B+b) ..... multiply both sides by 2
if it was 1/2 (h(B+b))
2A = h (B+b) ....divide both sides over (B+b)
2A/(B+b) = h
but if its 1/[2h (B+b)] that would be
A = 1/[2h (B+b)] .......... you multiply both sides by [2h (B+b)]
A [2h (B+b)] = 1.... divide by A
[2h (B+b)] = 1/A ..... divide by 2(B+b)
h = 1/[2A(B+b)]

hope i have helped wishing you all the luck

Answer 4

1.3!x+3!-5=10
=3!x+3!=15
!x+3!=15/3
!x+3!=5
x=2 have to take only positive value.

2.c=5/9(f-32)
9c=5f-32*5
9c=5f-160
9c+160=5f
f=(9c+160)/5

3 a=1/2(b+B)
2a=h(B+b)
h=2a/(B+b)