I hope this helps you
slope=y2-y1/x2-x1
slope=9-15/5-3
slope= -6/2
slope = -3
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Answer
Find out the how many pounds of metal are in 1,950 lb of ore .
To proof
let us assume that the pounds of metal are in 1,950 lb of ore be x .
As given
In an ore, 9.8% of its total weight is metal.
ore weight = 1,950 lb
9.8% is written in the decimal form

= 0.098
Than the equation becomes
x = 0.098 × 1950
x = 191.1 pounds
Therefore the 191.1 pounds of metal are in 1,950 lb of ore .
Hence proved