Given a = 2x ^ 2-3x-1, B = 3x ^ 2 + 2X-4, when x = - 12 / 13, find the value of 3a-2b

Given a = 2x ^ 2-3x-1, B = 3x ^ 2 + 2X-4, when x = - 12 / 13, find the value of 3a-2b

A = 2x & # 178; - 3x-1, B = 3x & # 178; + 2X-4, x = - 12 / 13
3A-2B=6x²-9x-3-(6x²+4x-8)=5-13x=17

1. (2x-y) square 2. (3a + 2b) square 3. (2P + Q) square 4. (X-Y) square 5. (1 / 3x-0.5y) square

1. (2x-y) square = 4x ^ 2-4xy + y ^ 2
2. (3a + 2b) square = 9A ^ 2 + 12ab + 4B ^ 2
3. (- 2p + Q) square = 4P ^ 2-4pq + Q ^ 2
4. (X-Y) square = x ^ 2 + 2XY + y ^ 2
5. (1 / 3x-0.5y) square = 1 / 9x ^ 2-1 / 3xy + 1 / 4Y ^ 2

(- 2a-3b) (2a-3b) is the square difference formula

Original formula = (- 3b-2a) (- 3B + 2a)
=(-3b)²-(2a)²
=9b²-4a²

Calculate (2a-1 / 3b) (- 1 / 3b-2a) with square difference formula

Write a fraction in the brackets and put forward the minus sign

Is (2a + 3b) (2a-3b) a square difference formula

The expression: (a + b) (a-b) = the product of the sum of square a and square B and the difference between the two numbers, which is equal to the difference between the two numbers. This formula is called the square difference formula of multiplication
(2a+3b)(2a-3b)=(2a)^2-(3b)^2 =4a^2-9b^2
yes

Known: a = 4x square - 4xy + y square, B = x square + XY + 7Y square, find the value of (3a-2b) - (2a + b)

（3A—2B)—（2A+B）
=3A—2B-2A-B
=A-3B
=2(4x²-4xy+y²)-3(x²+xy+7y²)
=8x²-8xy+2y²-3x²-3xy-21y²
=5x²-11xy-19y²

(x-1) - 2 (2x + 1) first remove the brackets and then merge the similar items

（x-1）-2（2x+1）
=x-1-4x-2
=-3x-3

1 / 2 (a + 4b) - 1 / 3 (3a-6b) first remove the brackets and merge the similar items

First remove the brackets, then merge the same type X + [x + 1 (- 2x-4y)] (a + 4b) - (3a-6b)
-[-（-a²）+b²]-[a²-（+b²）]

Original formula = x + (x-2x-4y)
=x+x-2x-4y
=-4y
Original formula = a + 4b-2a + 6B
=-a+10b

If the algebraic expressions 3A ^ 4B ^ 2x and 0.2A ^ 4B ^ 3x-1 can merge similar terms, then the value of X is

2x=3x-1
-x=-1
x=1