Do you have multiple choices?
Believe its 343
You'll be using point slope form to solve this.
As the name suggests, you'll need the slope as well as a point. To find the slope use the slope formula: 
Plug in the points.

The slope of this line is 5.
Point slope form is y-y1 = m(x-x1), so plug in the slope and a point into this equation. I'll use (0,8).
y-(8) = 5(x-(0))
1. Write this out without parentheses.
y-8 = 5(x)
2. Multiply 5 and x.
y-8 = 5x
3. Add 8 to both sides.
y = 5x+8
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Answer is:
y = 5x+8
Three tenths is the same as 3/10
the sum of -2 and -28 is -30
3/10 of -30 is the same as the products of the two
3 x -30 / 10 = -90/10 = -9
Your answer is
3(-2 + -28)/10 = -9