Question

Which equation in point slope form represents a line with m=-15 that goes through the point (7,-1)

Answer 1

The answer is:  " y = -15x + 104 " .
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  y = mx + b ;

 m = -15

 y  = -15x + b


When x = 7 ; y = -1 ; 


-1 = -15(7) + b


-1 = -105 + b ;
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Solve for "b" 
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  -1 = -105 + b ;  ↔  - 105 + b = -1 ; 

↔  b − 105 = -1  
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Add "105" to each side of the equation:
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    b − 105 + 105 =  -1 + 105 ;

    b =  104
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   y = mx + b ;   →   y = -15x + 104 .
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