No.151 Parallel Lines and a Shared Y-Intercept
POINT
Parallel lines have the same slope. If two lines intersect on the y-axis, they have the same y-intercept.
Example
1
Find the equation of the line through \( (2,-1) \) parallel to \(y=2x+5\).
\(y=2x-5\)
2
Find the equation of the line through \( (2,5) \) that intersects \(y=3x+4\) on the y-axis.
\(y=\frac12x+4\)
TRY
TRY 1
Through \( (1,4) \), parallel to \(y=3x-2\).
\(y=3x+1\)
TRY 2
Through \( (-2,1) \), parallel to \(y=-2x+5\).
\(y=-2x-3\)
TRY 3
Through \( (3,7) \), intersecting \(y=2x+1\) on the y-axis.
\(y=2x+1\)
TRY 4
Through \( (4,0) \), intersecting \(y=-x+2\) on the y-axis.
\(y=-\frac12x+2\)