SOLUTION: WHAT TYPE OF FORMULA AM I SUPPOSE TO USE IN ORDER TO FIND THE VALUE OF X 0R Y. THE DIRECTIONS SAY, "FIND THE VALUE OF X OR Y SO THAT THE LINE THROUGH THE PAIR OF POINTS HAS THE GIV

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Question 213427This question is from textbook PRECALCULUS
: WHAT TYPE OF FORMULA AM I SUPPOSE TO USE IN ORDER TO FIND THE VALUE OF X 0R Y. THE DIRECTIONS SAY, "FIND THE VALUE OF X OR Y SO THAT THE LINE THROUGH THE PAIR OF POINTS HAS THE GIVEN SLOPE." I'M NOT SURE HOW TO DO THAT. THE GIVEN IS (-2,3) AND (4,y) with the slope of -3. This question is from textbook PRECALCULUS

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WHAT TYPE OF FORMULA AM I SUPPOSE TO USE IN ORDER TO FIND THE VALUE OF X 0R Y. THE DIRECTIONS SAY, "FIND THE VALUE OF X OR Y SO THAT THE LINE THROUGH THE PAIR OF POINTS HAS THE GIVEN SLOPE." I'M NOT SURE HOW TO DO THAT. THE GIVEN IS (-2,3) AND (4,y) with the slope of -3.
:
Use the slope formula to find y: that is %28y2-y1%29%2F%28x2-x1%29 = m
Assign the given values as follows:
x1=-2; y1=3
x2 =4; y2= y
m = -3
:
Substitute the given values as follows and find y
%28y-3%29%2F%284-%28-2%29%29 = -3
%28y-3%29%2F%284%2B2%29 = -3
%28y-3%29%2F6 = -3
Multiply both sides by 6
y - 3 = 6(-3)
y = -18 + 3
y = -15; the pair is: 4,-15
;
Use the point/slope formula to find the equation
y - y1 = m(x - x1)
Substitute the given values
y - 3 = -3(x -(-2))
y - 3 = -3(x + 2)
y - 3 = -3x - 6
y = -3x - 6 + 3
y = -3x - 3 is the equation
:
Check solution by substituting the x value of 4
y = -3(4) - 3
y = = -12 - 3
y = -15 which is the value we got for y