I cant seem to understand this..
(w/21)-(w/49)=(1/21)
solve for w?
2 answers
hint: multiply each term by (3x49) or 147
We have a fractional equation. Your first goal should be to do away with the fractions. It is easier to work with equations that have no fractions.
What is the LCD of 21 and 49?
Reiny said 147.
147/21 = 7
147/49 = 3
Yes, 147 = LCD.
We multiply each term on BOTH sides of the equation by the LCD.
(w/21)(147) = 7w
-(w/49)(147) = -3x
(1/21)(147) = 7
We now have a linear (not fractional) equation:
7w - 3w = 7
4w = 7
w = 7/4....This is our answer or is it?
How do we know that w = 7/4? We plug 7/4 in the original fractional equation and simplify.
You were given:
(w/21)-(w/49)=(1/21)
Our goal: To get 1/21 on BOTH sides of the fractional equation.
7/4 divided by 21 - 7/4 divided by 49 = 1/21
1/12 - 1/28 = 1/21
1/21 = 1/21...IT checks!!!
This means that the answer is w = 7/4.
Done!
What is the LCD of 21 and 49?
Reiny said 147.
147/21 = 7
147/49 = 3
Yes, 147 = LCD.
We multiply each term on BOTH sides of the equation by the LCD.
(w/21)(147) = 7w
-(w/49)(147) = -3x
(1/21)(147) = 7
We now have a linear (not fractional) equation:
7w - 3w = 7
4w = 7
w = 7/4....This is our answer or is it?
How do we know that w = 7/4? We plug 7/4 in the original fractional equation and simplify.
You were given:
(w/21)-(w/49)=(1/21)
Our goal: To get 1/21 on BOTH sides of the fractional equation.
7/4 divided by 21 - 7/4 divided by 49 = 1/21
1/12 - 1/28 = 1/21
1/21 = 1/21...IT checks!!!
This means that the answer is w = 7/4.
Done!
6 answers