A professor determined the relationship between the time spent studying (in hours) and performance on an exam.
1 answer:
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Answer:
y = - 3x + 7
Step-by-step explanation:
The equation of a line in slope- intercept form is
y = mx + c ( m is the slope and c the y- intercept )
Calculate m using the slope formula
m =
with (x₁, y₁ ) = (2, 1) and (x₂, y₂ ) = (5, - 8)
m = =
= - 3 , thus
y = - 3x + c ← is the partial equation
To find c substitute either of the 2 points into the partial equation
Using (2, 1) , then
1 = - 6 + c ⇒ c = 1 + 6 = 7
y = - 3x + 7 ← equation of line
comparing the relation given
thus y= -2x +1 to the general equation of a line
where y= mx + c
where m is the gradient and c is the intercept on the y-axis.
from the question, the gradient is -2 and since the line is perpendicular, the gradient is given as
so substituting the value of m in to the equation
=
as the gradient
equation of line is given by
y - y1 = m( x-x1)
from the question y1= -2 and x1=1
substitute them
y-(-2) = 1/2 (x -1)
y+2 =1/2 (x-1)
multiplying through by 2
2 (y+2) = x-1
2y +4 = x-1
2y =x-1-4
2y =x-5
x -2y -5 = 0
therefore the equation for the line is x-2y -5=0