The solution to these four problems is the same, among which the fourth problem

The problem is the most complicated. Take this as an example.

The square of sine value plus the square of cosine value according to angle is equal to 1.

It is known that the square of the cosine of the inclination angle is equal to 9/25.

So the cosine of the tilt angle is 3/5 or -3/5.

Because we don't know whether the inclination angle is acute or obtuse, both results are possible and cannot be discarded.

(Because the sine value is positive in both acute and obtuse angles, the cosine value may be positive or negative. In question 3, it is given that the tilt angle is acute, so there is only one answer, which is equivalent to a short question in question 4)

So the tangent of the inclination angle, that is, the slope of the straight line, is 4/3 or -4/3.

So the equation of the straight line is: y=4/3x-2 or y=-4/3x-2.

(According to the inclination equation of a straight line)

As in the previous three methods, add the square of the sine value of an angle and the square of the cosine value equal to 1 to get the sine value and cosine value, and then get the tangent value (slope) according to the sine value and cosine value, and the slope is known, so as to get the linear equation.