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Explanation:
The line must go through the point (5,2) which means x = 5 and y = 2 pair up together.
We'll plug these x and y values into the equation and solve for b.
y = -3x+b
2 = -3(5)+b
2 = -15+b
2+15 = b
17 = b
b = 17
The equation y = -3x+b turns into y = -3x+17