We have two points, (3,0) and (0,-3). So we can find the slope of the line:
m=(y2-y1)/(x2-x1)
m=(-3-0)/(0-3)
m=-3/-3
m=1 so far for the line y=mx+b we have:
y=x+b, b is the y intercept which we were told is -3 so
y=x-3
The above is called the slope-intercept form of a line, y=mx+b, the standard form of a line is ax+by=c, so we need to get both variables on one side of the equation..
y=x-3 subtract x from both sides
-x+y=-3
While the above may be acceptable to some, technically the coefficient of x should be expressed as a positive value, so we should divide the above "solution" by -1 to get:
x-y=3
If we want to simplify Algebraic Fractions:
We have to take a look at the numerator and the denominator
Why? Because to simplify we need to have a common multiple.
When we find the common multiple, we now know by which factor we have to break down the fraction in the numerator and the denominator
I have some examples attached below for help.
Answer:

Step-by-step explanation:
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![\dfrac{8}{5} - \left[-\dfrac{2}{3}\right]](https://tex.z-dn.net/?f=%5Cdfrac%7B8%7D%7B5%7D%20-%20%5Cleft%5B-%5Cdfrac%7B2%7D%7B3%7D%5Cright%5D)




D, Because 7/15 + 9/15 is 16/15 + 4/15 =20/15 which equals 1 5/15 which turns into 1 1/3
A, 1/21 + 2/21 = 3/21 and that equals 1/7
C, 3/14+3/12 turns into 3/14+5/14= 10/14 - 8/14= 2/14=1/7