SOLUTION: 9(2X-1) 4(X-5) ------ = ----- 7 3

Algebra ->  College  -> Linear Algebra -> SOLUTION: 9(2X-1) 4(X-5) ------ = ----- 7 3      Log On


   

Question 70643: 9(2X-1) 4(X-5)
------ = -----
7 3
Found 2 solutions by checkley75, bucky:
Answer by checkley75(3666) About Me  (Show Source):
You can put this solution on YOUR website!
9(2X-1)/7=4(X-5)/3
(18X-9)/7=(4X-20)/3 NOW CROSS MULTIPLY WE GET
7(4X-20)=3(18X-9)
28X-140=54X-27
28X-54X=-27+140
-26X=113
X=113/-26
X=-4.436

Answer by bucky(2189) About Me  (Show Source):
You can put this solution on YOUR website!
9%2A%282x-1%29%2F7+=+4%2A%28x-5%29%2F3
.
This is in the form of a proportion ... two fractions set equal to each other. There are
ways that you can work through common denominators and do simplifications, but a common
method is that a lot of students use for solving proportions that aren't way complex is
to begin by cross-multiplying them ... multiplying the denominator on one side by the numerator
on the other side and setting the two products equal. For this problem the 7 would
multiply the 4%2A%28x-5%29 and the 3 would multiply the 9%2A%282x-1%29. You can do
that multiplication in your head and get the resulting equation:
.
28%2A%28x-5%29+=+27%2A%282x-1%29
.
Next do the multiplications on both sides to get:
.
28x+-+140+=+54x+-+27
.
The rest is straightforward. Add +140 to both sides to eliminate the 140 on the left side:
.
28x+=+54x+%2B+113
.
Then add -54x to both sides to eliminate the 54x on the right side:
.
-26x+=+113
.
Finally, to solve for x, just divide both sides by -26 and the answer becomes:
.
x+=+%28-113%2F26%29
.
That's the answer. If you do the division you get a decimal answer of 4.346153846.
.
Hope this helps you a little to see a way of working problems such as these that are in
proportional form. This method is not the only way the problem could be done, but it's
a convenient way at times.