2x - y = 7
Put this equation in slope intercept form, y = mx + b.
Solve for y by subtracting 2x from both sides.
- y = 7 - 2x
Divide both sides by -1.
y = -7 + 2x
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Perpendicular lines have opposite reciprocal slopes, so flip the slope of the line and change the sign.
The slope of this line: y = -7 + 2x is 2, so find the reciprocal and add a negative sign.
2 becomes -1/2, so your answer is:
A) -1/2