If a quadratic trinomial only contains the letter A, its coefficient of quadratic term is - 2, coefficient of primary term is 5, and constant term is - 10, then the polynomial

If a quadratic trinomial only contains the letter A, its coefficient of quadratic term is - 2, coefficient of primary term is 5, and constant term is - 10, then the polynomial

-2a^2+5a-10

There are three piles of apples. The first pile is 2 / 5 tons, 1 / 8 tons less than the second pile. The third pile is 1 / 8 less than the second pile. How many tons of apples are there in the third pile
There are three piles of apples. The first pile of apples is 2 / 5 tons, which is 1 / 8 tons less than the second pile. The third pile is 1 / 8 less than the second pile. How many tons of apples are there in the third pile? To calculate the process, it is better not to use the equation

Second pile = 2 / 5 + 1 / 8 = 21 / 40 tons
Third pile = (21 / 40) / (1-1 / 8) = 3 / 5 tons
The third pile has 3 / 5 tons of apples

[(Mn + 2) (mn-2) - 2m square, n square] / (MN), where M = 10, n = - 1 / 25

The original formula = (m ^ 2 * n ^ 2-4-2m ^ 2 * n ^ 2) / (m * n) = (- m ^ 2 * n ^ 2-4) / (m * n) = (substituting the number)=
ten point four

Mathematics. Calculation problems. (1), binary linear equations. {X-Y = 3, 2Y + 4 (X-Y) = 14

X = 4, y = 1, I calculated it myself, which is correct. My camera is not at home, so I don't put pictures

Factorization: 64x & # 178; Y & # 178; - (X & # 178; + 16y & # 178;) &# 178;

64x²y²-（x²+16y²）²
=(8xy+x²+16y²)(8xy-x²-16y²)
=-(x²+8xy+16y²)(x²-8xy+16y²)
=-(x+4y)²(x-4y)²

Simple calculation of 18 / 17 △ 19 + 1 / 19 × 16 / 17

18/17÷19+1/19×16/17
=18/17×1/19+1/19×16/17
=1/19 ×（18/17+16/17）
=1/19 × 2
=2/19

First simplify, then evaluate: 2x & # 178; - 2Y & # 178; divide 4x & # 178; - 8xy + 4Y & # 178; multiply XY (X-Y) divide (x + y) &# 178;, where x = 2, y = 3

Original formula = 4 (X-Y) & # / 2 (x + y) (X-Y) * (x + y) / XY (X-Y)
=2(x-y)/(x+y)*(x+y)/xy(x-y)
=2/xy
=2/(2*3)
=1/3

2 yuan a jin of cucumber, 8 yuan 3 cents of cucumber is how many grams?
There are 17 cucumbers in total. How many grams are each?
I am a person who doesn't like to count, please

1 kg = 500 g = 2 yuan. So 1 g = 4 cents. So 8 yuan 3 Mao = 8 yuan + 3 Mao, that is 8 × 500 + 3 / 0.4 = 4007.5 G

Quadratic factorization of M + n) - 4m (M + n) + 4m

(m+n)²-4m(m+n)+4m²
=m²+2mn+n²-4m²-4mn+4m²
=m²-2mn+n²
=(m-n)²

-24 × (7 / 12-5 / 6)
+(- 2.4) + (- 1.68) - (- 2 / 5 of 4) - (- 1.68)
If it can be simple, it will be simple. There must be a process

-24 × (7 / 12-5 / 6)
=-7 / 24 × 12 + 5 / 24 × 6 + 24 × 1
=-14+20+24
=30
+(- 2.4) + (- 1.68) - (- 2 / 5 of 4) - (- 1.68)
=-2.4-1.68+4.4+1.68
=（4.4-2.4）+（1.68-1.68）
=2+0
=2