20. parallel lines will have the same slope, but different y intercepts
In y = mx + b form, the slope is in the m position and the y intercept is in the b position.
So y = 3x + 4 and y = 3x + 6 are parallel lines
21. perpendicular lines will have negative reciprocal slopes.
lets say u have a line..y = 2/3x + 4....the slope here is 2/3. To find the negative reciprocal, flip the slope and change the sign. So we have 2/3, flip the slope making it 3/2, change the sign making it -3/2. So ur perpendicular line will have a slope of -3/2.
so ur equations can be : y = 2/3x + 4 and y = -3/2x + 4
22. y = 2x + 5...slope here is 2. Parallel lines have the same slope.
y = mx + b
slope(m) = 2
(-3,1)...x = -3 and y = 1
sub and find b, the y int
1 = 2(-3) + b
1 = -6 + b
1 + 6 = b
7 = b
so this equation is : y = 2x + 7
23. 4x + 3y = (I cant see the last number..but we dont need it)
3y = -4x + ?
y = -4/3x + ?.....slope here is -4/3. A perpendicular line will have a negative reciprocal slope. So out perpendicular line will have a slope of 3/4.
y = mx + b
slope(m) = 3/4
(-8,-5)...x = -8 and y = -5
sub and find b, the y int
-5 = 3/4(-8) + b
-5 = - 6 + b
-5 + 6 = b
1 = b
so ur equation is : y = 3/4x + 1
