The problem of finding the absolute value of mathematics in the first volume of the seventh grade 1. If the absolute value of a is equal to 2 and B is equal to 1, then the absolute value of a + B is? 2. The detection results of some football are negative 25, positive 10, negative 20, positive 30, positive 15, negative 40, which football is of good quality, and use the knowledge of absolute fat to explain. 3. It is known that A.B is a rational number, and / 3a-1 / + / 2b-5 / = 0, you can find the value of a and B according to the definition of absolute value 4. / A-1 / equals 4, then a is equal to?

The problem of finding the absolute value of mathematics in the first volume of the seventh grade 1. If the absolute value of a is equal to 2 and B is equal to 1, then the absolute value of a + B is? 2. The detection results of some football are negative 25, positive 10, negative 20, positive 30, positive 15, negative 40, which football is of good quality, and use the knowledge of absolute fat to explain. 3. It is known that A.B is a rational number, and / 3a-1 / + / 2b-5 / = 0, you can find the value of a and B according to the definition of absolute value 4. / A-1 / equals 4, then a is equal to?

1. The absolute value of a is 2, a = - 2 or 2, a + B = - 1 or 3, so the absolute value of a + B is 1 or 3
2. The closer the absolute value is to 0, the better, so the absolute value of positive 10 is the smallest, so positive 10 is good
3. The absolute value of any number is greater than or equal to 0. The sum of two numbers greater than or equal to 0 is 0, and these two numbers must be 0
So 3a-1 = 0, a = 1 / 3, 2b-5 = 0, B = 5 / 2