Speed up the math problem 1. The selling price of a certain type of mobile phone in June is 2000 yuan. After two successive price cuts, the current selling price is 1280 yuan. If the percentage of each price cut is the same, calculate the percentage 2. It is known that the equation (a + 2) x & # 178; - (2a-1) x + a = 0 has two unequal real roots, and the value range of a is obtained 3. It is known that the univariate quadratic equation x & # 178; + 2mx + (M + 2) * (m-1) = 0 (M is a constant) (1) If the equation has two unequal real roots, find the value range of M; (2) If the equation has two equal real roots, find the value of M; (3) If the equation has no real root, find the value range of M It's better to have a process and some bonus points

Speed up the math problem 1. The selling price of a certain type of mobile phone in June is 2000 yuan. After two successive price cuts, the current selling price is 1280 yuan. If the percentage of each price cut is the same, calculate the percentage 2. It is known that the equation (a + 2) x & # 178; - (2a-1) x + a = 0 has two unequal real roots, and the value range of a is obtained 3. It is known that the univariate quadratic equation x & # 178; + 2mx + (M + 2) * (m-1) = 0 (M is a constant) (1) If the equation has two unequal real roots, find the value range of M; (2) If the equation has two equal real roots, find the value of M; (3) If the equation has no real root, find the value range of M It's better to have a process and some bonus points

(1) Note: A ^ B is the B power of A. suppose that the percentage of each price reduction is X2000 * (1-x) ^ 2 = 1280 (1-x) ^ 2 = 0.641-x = 0.8 and 1-x = - 0.8x1 = 0.2 = 20% x2 = 1.8 (rounding off). Answer: the percentage is 20% (2) because there are two inequalities, so [- (2a-1)] ^ 2-4 * [(a + 2) * a] > 04A ^ 2-4a + 1-4a ^ 2-8a