The key to solve the problem is to use the undetermined coefficient method, similar triangles's judgment and properties, Pythagorean theorem and other methods to find the quadratic resolution function, and then get △PMQ∽△NBR, and then get the value of n 。

Using the known coordinates of point A and point B, and then using the undetermined coefficient method to get the values of point A and point B;

The second question, known as MN=d and PF=t, can be seen from the figure that MN=MF+FN. We might as well replace MF and FN with PF. By using the properties of right triangle and 45 parallel lines, we can get the relationship between MN and PF: FN=PF=t, ∠MPF=∠BOD = Tan.

Solution: (1)∵y=-x+4 intersects the X axis at point A,

∴A(4,0)，

∵ The abscissa of point B is 1, and the straight line y=-x+4 passes through point B,

∴B( 1,3)，

This is the answer/exercise/math /800902. Have detailed ideas and solutions. In plane rectangular coordinates, point O is the coordinate origin, straight line y=-x+4 intersects with X axis at point A, parabola y=ax2+bx passing through point A intersects with straight line y=-x+4 at another point B, and the abscissa of point B is 1.

This question is not very difficult. After grasping the key points, calm down and analyze step by step. Don't worry. I believe you will understand after reading the answer. If you don't understand, you can keep asking me. Dear, I hope you can give me an adoption!