math wiz need help please. thanks.?

Question

1. Solve for x: (3/5)(10x – 4) + 1/5 = 49

2. Solve for d: (5/3)d + 2 = p

3.Solve for a: | a – 7 | = 4

4.Solve for x:
| x -2|
| 6 2x| = 10x

5.Use Cramer’s rule to solve:
x - 9y = 2
3x + 4y = 7

6.Solve: (1/y) - (2/3) = (1/4)

Answer 1

OK, I'll get you started:
1) 3/5(10x-4)+1/5 = 49
First, try to get the "x" more alone.
a) subtract 1/5 from both sides to get 3/5(10x-4)= (49-1/5)
b) multiply both sides by 5/3 to get (10x-4) = 5*(49-1/5)/3
c) add 4 to both sides to get 10x = 5*(49-1/5)/3 + 4
d) divide both sides by 10, and I'm going to let you do the rest.

2) 5/3d+2=p. This is easier than #1 as long as calling "p" a number doesn't throw you off.
a) subtract 2 from both sides: 5/3d=p-2
b) multiply both sides by 3: 5d = 3*(p-2)
c) divide both sides by 5 - you can do it from here

3) |a-7| = 4
which means that either (a-7) = 4 or (a-7) = -4
So there are two possibilties. I'll do the first: if a-7 = 4, then a = 11.

4) I'm not sure I understand this one.

5)Here is a great web page that tells you exactly how do to this
http://www.purplemath.com/modules/cramers.htm

6) 1/y - 2/3 = 1/4
a) add 2/3 to both sides. 1/y = 1/4 + 2/3 = 3/12 + 8/12 = 11/12
b) Multiply both sides by y: 1 = 11/12*y
c) divide both sides by 11
d) multiply both sides by 12