Question 1169670
if you have a calculator, then this is most easily done by using it.
you should save all intermediate results into a memory location so that as many of the decimal digits can be saved as possible.


your original equations are:
3/5 * x - 4 * y = -1
0.8 * x - 3.5 * y = 1/2


convert the equations to decimal form to get:
.6 * x - 4 * y = -1
.8 * x - 3.5 * y = .5


multiply both sides of the first equation by 7 and multiply both sides of the second equation by 8 to get:
4.2 * x - 28 * y = -7
6.4 * x - 28 * y = 4


subtract the first equation from the second to get:
2.2 * x = 11


solve for x to get:
x = 11/2.2 = 5


in the first equation, replace x with 5 to get:
3/5 * x - 4 * y = -1 becomes:
3/5 * 5 - 4 * y = -1 which becomes:
3 - 4 * y = -1
subtract 3 from both sides of the equation to get:
-4 * y = -4
solve for y to get:
y = 1


you have:
x = 5 and y = 1


replace x and y with those values in both the original equations to get:


3/5x - 4y = -1 becomes:
3/5 * 5 - 4 * 1 which becomes:
3 - 4 = -1 which becomes:
-1 = -1
this confirms the first equation is true when x = 5 and y = 1.


0.8x - 3.5y = 1/2 becomes:
.8 * 5 - 3.5 * 1 = 1/2 which becomes:
4 - 3.5 = 1/2 which becomes:
.5 = 1/2 which becomes:
1/2 = 1/2
this confirms the second equation is true when x = 5 and y = 1.


your solution is that x = 5 and y = 1


the graph of both equations is shown below.


<img src = "http://theo.x10hosting.com/2020/111303.jpg">


the intersection point is at (x,y) = (5,1)


that confirms graphically that your solution is at x = 5 and y = 1.