Easy algebra question hellpp

i have the answers for all of them i just dont know how to do these!! PLEASEEE HELLP(:


1. Write an equation to find the sum of 3 consecutive odd integers that equal 33.
is it n+n+n+1=33

2. 9=3/x+1
the answer is -2/3 i just don't know how to do it.

3. The ratio of red to blue marbles in a bag is 4 to 5. If there are 180 marbles total, how many of the marbles are red?
answer: 80 red marbles

4. Write the equation of the line in Standard Form that passes through (3,6) and has a slope of 2/3

1)
For simpler calculation let the 3 consecutive odd integers be x-2,x and x+2.
Solving you will get 3x=33 or x=11. The numbers are 9,11 and 13

2)
9=3/x+1
multiplying both sides by (x+1)/9 assuming x not equal to -1
x+1=3/9=1/3 or x=1/3-1=-2/3

x= - 2/3

3)
Let the number of red marbles be 4x, then that of blue marbles is 5x. Total=9x=180
or, x=20
Or the number of red marbles =4x=4*20=80

4)
Standard equation of the line is y=mx+c where m is the slope.
Here, m=2/3 or
y=2/3*x+c. To determine c, put x=3, y=6 and solve for c
6=2/3*3+c =>6=2+c +>c=4
Equation of the line: y=2/3x+4 or 3y=2x+12

1. 7+9+13=33