We know that the first-order function y = - 2x + 4 intersects with the x-axis and y-axis, and points a and B (1) make the isosceles triangle ABP with ab as the edge, if P is in the first quadrant (1) Make an isosceles triangle ABP with ab as the edge. If P is in the first quadrant, ask for the coordinates of point P (2) Under the conclusion of 1, make a parallel line of line AB through point P, intersect the x-axis, Y-axis with point C and point d respectively, and calculate the area of quadrilateral ABCD The first question is wrong. It's an isosceles right triangle

We know that the first-order function y = - 2x + 4 intersects with the x-axis and y-axis, and points a and B (1) make the isosceles triangle ABP with ab as the edge, if P is in the first quadrant (1) Make an isosceles triangle ABP with ab as the edge. If P is in the first quadrant, ask for the coordinates of point P (2) Under the conclusion of 1, make a parallel line of line AB through point P, intersect the x-axis, Y-axis with point C and point d respectively, and calculate the area of quadrilateral ABCD The first question is wrong. It's an isosceles right triangle

A(2,0) B(0,4)
The second question should be: make equilateral triangle ABP with ab as the edge
Let P (x, 1 / 2x + 1.5) be PM ⊥ x to m, because it is equilateral, so AB = BP = 2 times root sign 5. In RT △ APM, Pythagorean is (X-2) &# 178; + (0.5x + 1.5) &# 178; = 20, because in the first quadrant, x > 0, so x = 1 + 2 root sign 3, Then we can get P (1 + 2 times root number three, 2 + root number three)
With the foundation of the second question, the third question will be much better. Let's set the straight line CD: y = - 2x + B, bring in P, and get b = 5, root sign 3 + 4
The C and D coordinates are (2.5 times root sign 3 + 2,0) and (0,5 times root sign 3 + 4) respectively
Calculate s △ OCD = quarter (91 + 40 root sign three), subtract s △ AOB to get quadrilateral area of 75 / 4 + 10 root sign three