math help please..please..solving for x....its so hard?

Question

1. bx + c = d + 3x
2. 2ax + b2 = 4a2 + bx
3. x + 7/ 3a = 5/6 + a
4. 1/b + 1/x = 1/c - 1/x

Answer 1

1.

bx + c = d + 3x
or, bx - 3x = d - c
or, x (b - 3) = d - c
or, x = (d - c) / (b - 3) [Answer]


2.

2ax + b^2 = 4a^2 + bx
or, 2ax - bx = 4a^2 - b^2
or, x (2a - b) = (2a)^2 - b^2
or, x = (2a + b) (2a - b) / (2a - b) [As, x^2 - y^2 = (x+y)(x-y)]
or, x = 2a+b [Answer]


3.

x + 7/ 3a = 5/6 + a
or, x = 5/6 + a - 7/3 a
or, x = 5/6 - 4/3 a [Answer]


4.

1/b + 1/x = 1/c - 1/x
or, 1/x + 1/x = 1/c - 1/b
or, 2/x = (b - c)/bc
or, 1/x = (b - c)/2bc
or, x = 2bc/(b-c) [Answer]

Answer 2

1) bx+c=d+3x
bx-3x = d-c
x(b-3) = d-c
x = d-c/b-3

2) 2ax+b2 = 4a2+bx
2ax-bx = 4a2-b2
x(2a-b) = 4a2-b2
x = (2a+b)(2a-b)/(2a-b)
x = 2a+b

3) x+7/3a = 5/6 + a
x = 5/6 + a -7/3a
x = 5/6 + (-4/3a)
x = (5-8a)/6

4)1/b + 1/x = 1/c - 1/x
2/x = 1/c - 1/b
2/x = (b-c)/bc
2bc = x(b-c)
x = 2bc/(b-c)

Answer 3

Standard method!

1. Clear any fractions involving x (like in problem 4). Often it's simplest to clear ALL fractions.

2. Get all terms involving x on the left side, and all the other terms on the right.

3. Factor out x from the left side

4. Divide by the term multiplying x. This leaves x all by itself on the left, so that's the solution.

Simplify as you go! Do only one thing at a time so you are sure of every step and can check it. Don't be afraid to write out intermediate steps, this way you won't screw up.

E.g. in problem 4,

Step 1. Multiply by bcx to clear fractions
bcx/b + bcx/x = bcx/c - bcx/x
cx + bc = bx - bc
(in other problems you may need to find a common denominator....)

Step 2. cx - bx = -bc - bc = -2bc

Step 3. x(c - b) = -2bc

Step 4. x = (-2bc)/(c-b)

These problems are tedious but the method is cut & dried, and after doing a lot of them you will gain confidence.

Answer 4

1. bx + c = d + 3x
2. 2ax + b2 = 4a2 + bx
3. x + 7/ 3a = 5/6 + a
4. 1/b + 1/x = 1/c - 1/x

1
bx + c = d+3x
bx-3x=d-c
x(b-3)=d-c
x=(d-c)/(b-3)

2
2ax + b2 = 4a2 + bx
2ax-bx = 4a2-b2
x(2a-b)=4a2-b2
x=(4a2-b2)/(2a-b)
x=(2a-b)(2a+b)/(2a-b)
x=2a+b

3
x + 7/ 3a = 5/6 + a
x=5/6+a-7/3a
Note: I'm note sure if that is 7/(3a) or (7/3)a

4
1/b + 1/x = 1/c - 1/x
1/b = 1/c-2/x
1/c-1/b=2/x
x=2/(1/c-1/b)

Answer 5

bx + c = d + 3x

transpose bx

bx + c - bx = d + 3x - bx

c = d + 3x - bx

Transpose d

c -d = d + 3x - bx - d

c - d = 3x - bx

Factor x on the right side of the equation

c - d = x(3 - b)

Divide both sides of the equation by (3 - b)

c - d / (3 - b) = x(3 - b) / (3 - b)

c - d / (3 - b) = x

- - - - - - - - s-

Answer 6

sturdy one! As for the final time I did some "somewhat troublesome maths", i think of it could have been approximately thirteen years in the past....whilst i replaced into 18 years previous and an A-point student. i actually dropped down from A-point maths to AS-point....and that i did no longer even pass the AS.

Answer 7

number 1, did they give you any other values?
number 2, you have to isolate x in order to solve for it.