1) One piece of land is a right triangle with two right-angled sides of 6m and 8m respectively. Now it is necessary to expand this land into an isosceles triangle, and the expanded part is a right triangle with a right angle of 8m. What is the circumference of the unfolded isosceles triangle land? Answer: 20+ root 5 2) In the triangle abc, ad is the center line of bc side, and the angle adc is equal to 30. Fold the triangular adC along AD so that point C falls on c'. If bc=4, what is the length of bc'? Answer: No. 3) In the diamond-shaped abcd, the angle A = 1 10, e and f are the midpoint of the ab side and bc side respectively, and ep is perpendicular to the cd at point P, so what is the angle fpc? Answer: 55 4) February 2008-2007 2009 answer:15) February 2008-4016 times 2007+2007 2 answer: 1 6) (A+B) 2-6 (A+B). Where a=-0.75 and b=3 Answer: 9 7 of 16) Given a+c-7=0, find the value of (A+B) 2-2 (A+B) (B-C)+(C-B) 2. Answer: 49 8) Prove that the polynomial (n+7) 2-(n-5) 2 can be divisible by 24 for any natural number n. Answer: The original formula is equal to (n+7+n-5) (n+7-n+5) =12 (2n+2) = 24 (n+1) 9) polynomial x 2-my 2, where m is 10. Answer: m=4, 16, 64, 36. I'll give you a chance to lose the 2 1 below the ninth lane first. Goodbye. I'm back. Let's move on. 10) Regarding the fractional equation M = 1 in which x is divided by x-5, the following statement is correct: When the point solution of equation A is x=m-5 Bm greater than -5, the solution of the equation is positive, and when Cm is less than -5, the solution of the equation is negative, so the answer cannot be determined: C.