· Perpendicular lines have slopes that are opposite reciprocals of each other
· Slope-intercept form is y = mx + b, where m is the slope and b is the y-intercept
If the slope of the first line is 3, the slope of the second line is -1/3. Since the lines intersect at the origin, neither of them have a y-intercept.
6 x 89 is 534 6 x (90 - 1) is 534. BUT you have to subtract 90 from 1 and that's 89. So then you multiply 6 by 89. 6 x 90 is 540 and 6 x 1 is 6. you take 540 subtract 6 and that's 534. 540 - 6 is 534.
