Final answer:
Perpendicular lines have slopes that are negative reciprocals of each other, as shown in the slope-intercept equation y = mx + b, which defines straight lines with 'm' as the slope and 'b' as the y-intercept.
Step-by-step explanation:
The statement that two lines with slopes m1 and m2 are perpendicular if m1 = (-1)/(m2) refers to the relationship between the slopes of two lines in a Cartesian coordinate system. When two lines are perpendicular, their slopes are negative reciprocals of one another.
The general equation of a straight line in slope-intercept form is y = mx + b, where m represents the slope and b represents the y-intercept. The slope m tells us how steep the line is, calculated as rise over run (the change in y divided by the change in x). If one line has a slope of 3, as mentioned in Figure A1, then a line perpendicular to it will have a slope of -1/3. This example shows us how different values of m and b determine specific lines on a graph with x represented on the horizontal axis and y on the vertical axis.