Which line has an undefined slope? x=18, 2y-6x=0, y=-9, y=x

We know that

slope m=(y2-y1)/(x2-x1)
then

 case a) x=18
m=(y2-y1)/(18-18)> is undefined, because the denominator is zero

case b) 2y-6x=0
2y=6x> y=3x
the slope m=3> m is defined

case c) y=9
m=(9-9)/(x2-x1)> m=0> m is defined

case d) y=x
m=1> m is defined

the answer is
x=18 has an undefined slope

Wednesday1.) < 2.) 1961015.)6.486.)68.761 can be rounded up to 69i can't truly see the rest and my next comment will be thursday

Intersecting secant-tangent theorem states that if a tangent segment and a secant segment are drawn to a circle from an exterior point, then the square of the measure of the tangent segment is equal to the product of the measures of the secant segment and its external secant segment.so to break it down: 1. pq acts as the tangent and ps as the secant with an intersection at p.sr = 21rp = 3x + 3pq = 4x + 4following to equation: tangent squared = the two segments multiplied by each otherso (4x + 4) ^ 2 = (3x + 3) • (21) simplifies to 16x^2 - 31x - 47 = 0 or (16x - 47)(x + 1) x = -1 or x = 47/162. pq acts as the tangent and ps as the secant with an intersection at p (again! )sr = 16rp = xpq = 15(15) ^ 2 = 16 • x225 = 16xx = 225/163. the interesting chords are proportional to each other so a ratio is possible to set up: ap dp 10 3 + x = = —— = pc pb 8 xcross multiple to get 10x = (3 + x)(8)x = 12