Ok first we calculate the length of board without losses:
4 * 11.5 = 46 inches
then, we have 1 inch of waste allowed fir each piece, so the total waste is 4*1 = 4 inches
finally, we will add the length of the waste to the desired length to get the total length of the board as follows:
total length of board = 46+4 = 50 inches
Since the equation is in y = mx+b form you can easily determine the y intercept based on the b value present.
Y = mx + b
Y = 2x - 3
B = y intercept = (0,-3).
Question is using standard formula ax+by=c to find the slope by converting into slope intercept form y=mx+b
so we also need to convert ax+by=c into y=mx+b as shown below:



divide both sides by

Now compare it with y=mx+b, we get

So using values of a and b, we can find the slope
compare given equation -5x+2y=15 with ax+by=c, we get:
a=-5, b=2
Now plug both into above formula



Now matching these details with given choices we find that THIRD choice is the final answer.
the correct answer is 83.
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