a. y=1/2x-2
b. y=-1/2x+3
c. y=2x+1
d. y= -2x+4
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d. y=-2x+4
this is because in the formula used y=mx+b, b is represented as the the "y" intersept, which is 4. the slope, which is -2, is represented as x in this formula. therefore, D. y=-2x+4 is the correct answer