M is the midpoint of AB.
AM = = 4x - 8
MB =
5x-3/3
Find x and AB

X=-7 AB=-72

steps

since m is a midpoint, AM and MB are congruent so you set the two equations equal to each other, 4x-9=5x-3/3( is this a typo? bc 3/3 is 1)
subtract 4x from both sides m, -8=x-1
add 1 to both sides
x=-7

then plug -7 in for x 4(-7)-8=-36
since the two segments are congruent u do -36 x 2= -72

answer:

140

step-by-step explanation:

given that ab and bc are two tangents from point b

a and c are points of contact.

arc ac is 160 degrees means central angle subtended =320

and minor arc subtends 360-320 =40 degrees

consider the quadrilateral formed by the vertices a,b,c and o the centre of the circle

aoc = 40 degrees

at the point of contact tangents are perpendicular to radius hence other two angles are 90 each.

hence the 4th angle abc = 360-(90+90+40) =140

(since sum of angles of quadrilateral is 360)