Question

Identify the point (x1, y1) from the equation: y – 7 = 3(x + 2)

(–7, 2)
(7, –2)
(–2,7)
(2, –7)


I know the answer is 2,7 but which one is negative???? that's what confuses me

Answer 1

Its easy my dear friend....
just substitute every point in the given eqution...
if any point satisfies the eqution then that point is (x1,y1)

Answer 2

i think (–2,7)

7-7 = 3(-2+2)
0=0

Answer 3

So the point slope equation is
\[y-y _{1}=m(x-x _{1})\]
You can read off the solution :
y-7 on the left hand side, thus y1=7
3(x+2) on the right hand side, thus x1=-2 (I hope it is clear why -(-)=+)

Answer 4

Another way to identify is....
if we place 7 in y left handside part will become zero
then
-2 in place of x then right hand side part will become zero
so, answer must be (-2,7)