Answer:
Point slope form
y - 9 = 4(x-1)
Equation of the straight line passing through the point (1,9) and slope 'm' = 4 is 4 x - y +5=0
Step-by-step explanation:
<u><em>Step(i):-</em></u>
Given that the points are (1,9) and (-1,1)
slope of the line

m = 
m = 4
<u><em>step(ii):-</em></u>
Equation of the straight line passing through the point (1,9) and slope 'm' = 4
y-y₁ = m( x-x₁)
y - 9 = 4(x-1)
y -9 = 4x-4
4 x - y -4+9 =0
4 x - y +5=0
Equation of the straight line passing through the point (1,9) and slope 'm' = 4 is 4 x - y +5=0
The first y equals -3 and the second y equals -9
For the average to be 90,
(99 + 93 + x) / 3 = 90
or 192 + x = 270
or x = 270 - 192 = 78
Jim must score at least 78 in the third test.