7 copies of 1 fourth
2 answers:
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Answer:
C.
Step-by-step explanation:
Alan and his classmates found that the line of best fit through the data had the equation
The slope of this line is
If a line would intersect this line of best fit at right angles, then the two lines are perpendicular to each other.
The slopes of perpendicular lines are negative reciprocals of each other,
Hence that line must have slope
Therefore we look for a line whose slope is from the given options.
That line is the third option
The first equation, 8x - 9y = - 23
Obtain the equation in slope- intercept form
y = mx + c ( m is the slope and c the y-intercept )
to calculate m use the gradient formula
m = ( y₂ - y₁ ) / ( x₂ - x₁ )
with (x₁, y₁ ) = ( , 3) and (x₂, y₂ ) = (- 4, - 1 )
m = = (- 4)/-
=
partial equation is y = x + c
to find c substitute either of the 2 points into the partial equation
using (- 4, - 1 ), then
- 1 = - + c ⇒ c =
y = x +
← in slope- intercept form
the equation of a line in standard form is
Ax + By = C ( A is a positive integer and B, C are integers )
rearrange the slope- intercept equation into this form
multiply through by 9
9y = 8x + 23 ( subtract 9y and 23 from both sides )
8x - 9y = - 23 in standard form