Calculate question 1 (a + 2b-3c) (a-2b-3c) question 2 (2a + b) ^ 2 (2a-b) ^ 2

Calculate question 1 (a + 2b-3c) (a-2b-3c) question 2 (2a + b) ^ 2 (2a-b) ^ 2

In the reaction 2A + 2B = 3C + 4D, it is known that the relative molecular weight ratio of B, C and D is 16:22:9. Now, if 7.2g D is produced, how many grams of a are involved in the reaction

2A + 2B === 3C + 4D
2a 2*16 3*22 4*9
According to the law of conservation of mass
2a+32=66+36
2a=70
2 g D
70/m(A)=36/7.2
m(A)=14(g)

Calculation: (1) (2m + 3n) (2m-3n) (2) (- 3a-1 / 2b) (- 3A + 1 / 2b) (3) (- 4x + y) (y + 4x)

It's all square difference
The original formula = 4m & # 178; - 9N & # 178;
The original formula = (- 3a) &# 178; - (1 / 2b) &# 178;
=9a²-1/4b²
Original formula = (y-4x) (y + 4x)
=y²-16x²

When a = 0.25, B = - 0.37, the value of the square of the algebraic formula a + the square of a (a + b) - 2A - AB

When a = 0.25, B = - 0.37,
Square of algebraic formula a + square of a (a + b) - 2A ab
=a²+a²+ab-2a²-ab
=2a²-2a²
=0

If the square of a + 25 + \ B + 1 \ = 10a, then the value of the algebraic formula (a + b) - 2 is the absolute value of the square of a + 25 + B + 1

a^2-10a+25+|b+1|=0
(a-5)^2+|b+1|=0
The sum of absolute value and square is greater than or equal to 0, and the sum is equal to 0. If one is greater than 0, then the other is less than 0
So both are equal to zero
So a-5 = 0, B + 1 = 0
a=5,b=-1
(a+b)^(-2)
=4^(-2)
=1/16

Teacher Zhang asked the students to calculate "when a = 0.25, B = - 0.37, the value of the quadratic power of the algebraic formula a + the quadratic power of a (a + b) - 2A - AB"
Xiao Gang said that the result can be obtained without conditions. Do you think his argument is reasonable?

a²+a(a+b)-2a²-ab
=a²+a²+ab-2a²-ab
=0

1. If the rational numbers a and B satisfy the second power of 3a-1 + (b-2) = 0, then the value of the B power of a is? 2
1. If the rational numbers a and B satisfy the second power of 3a-1 + (b-2) = 0, then the value of B power of a is?
2. Take any four natural numbers between 1 and 13, and carry out "+, -, ×, △" operations on these four numbers (and each number can only be used once), so that the result is 24__________

wolai

If (the second power of a-3a-1) + a = the second power of A-A + 4, then a=______

A=a²-a+4 - (a²-3a-1)=2a+5

(2 + 3a to the second power) (3a to the second power - 2)

(2+3a²)(3a²-2)
= (3a²)² - 2²
= 9a^4 - 4

If a 〈 0, - 1 〈 B 〈 0, then what is the order of squares of a, AB, AB from small to large
Urgent
Brother and sister, help

This kind of problem can be known as ~ AB > AB square > A with a try