Shenzhen Luohu photography parent-child photo

Personal idea

Let the analytical formula of this straight line be y = kx+b[ formula 3]. Note: y = 1/2x- 1[ formula 1]y =-x-3[ formula 2].

Because Formula 3 is cut by Formula 1 and Formula 2, there is an intersection.

Therefore, the column1/2x-1= kx+b [5 #]-x'-3 = kx'+b [6 #].

And because the midpoint is (0,3) on the Y axis, if we substitute 3#, we can get that B = 3, X and X' are symmetrical about Y axis, so we can get the conclusion that X' =-X.

Therefore, equation 5#6# can be simplified to1/2x-1= kx+3 [7 #] x-3 =-kx+3 [8 #], and then k =-110 can be obtained.

So the original analytical formula is y =-110x+3.

test method

The two x values can be substituted into 1, 3 and 2, 3, respectively, to find out whether their y values are the same, and then draw a coordinate system and mark these three points; A line connects two intersections to see if it passes through (0,3) and is equally divided by it. Ok ~ \ (≥ ▽≤)/~ La La La.