This kind of problem is simplified and sorted into a standard form of point-oblique equation. Sometimes you may need to use this straight line with unknown slope to solve the problem, so you need to use the above writing method.
2.ac & lt0, bc<0 means that A, B and C cannot be 0, so the straight line is written in the form of oblique specification.
Y=(-a/b)(x+c/a) It can be seen that the equation passes through the fixed point (-c/a, 0), and on the right side of the X axis, the slope is >; 0, so you can see that the straight line does not pass through the second quadrant when drawing.
3. The answer to the third question is-1/3.
This is an exercise of the formula of the distance from a point to a straight line, and the answer is your answer.
This question applies to the application of your first question.
Let the equation of a straight line be y-2=k(x+ 1) and get y=kx+k+2.
Then the problem is transformed into the problem that the distance from the origin to the straight line y=kx+k+2. Bring in the distance formula from point to straight line and calculate k=- 1 or k=-7.
6. The P coordinate (0, 1), and the P point is not on the given straight line, so
Let the straight line be 2x+ 1 1y+C=0.
Then the distance from point P to 2x+11y+16 = 0 is equal to the distance from the expected straight line 2x+ 1 1y+C=0.
Introduction formula of distance from point to straight line
Get C= 16 (because it coincides with a given straight line) or C=-38.
The linear equation is 2x+ 1 1y-38=0.