4x(x-y)-(2x-3y)(2x-3y) x=1 y=-1

4x(x-y)-(2x-3y)(2x-3y) x=1 y=-1

4x(x-y)-(2x-3y)(2x-3y)
=4x^2-4xy-4x^2-9y^2+12xy
=8xy-9y^2
=8*1*(-1)-9(-1)^2
=-8-9
=-17

It's interesting. I want to challenge you
There are three green apples, five yellow apples and seven red apples. The weight of each one is about 1.16 kg (rounding method). How many kg do the three green apples, five yellow apples and seven red apples weigh?

Let three green apples, five yellow apples and seven red apples be a, B and C. A, B and C are all positive integers

A kind of savings with compound interest. The principal is a yuan, and the interest rate of each period is R. suppose the sum of principal and interest is y, and the deposit period is X. write out the analytic function of the change of principal and interest with the deposit period X. if the principal is 1000 yuan, and the interest rate of each period is 2.25%, try to calculate the sum of principal and interest after five periods (accurate to 1 yuan)?

According to the meaning of the question: 1-year maturity interest is: y = a (1 + R), 2-year maturity interest is: y = a (1 + R) 2, 3-year maturity interest is: y = a (1 + R) 3, ｜ y = a (1 + R) x (x ∈ n *), a = 1000, r = 2.25%, x = 5, y = 1000 × (1 + 2.25%) 5 = 1000 × 1.02255 ≈ 1118

Given that a (x12002), B (x22002) are two points on the parabola y = ax ^ 2 + BX + C, then when x = X1 + X2, the value of quadratic function is ()
A.2b^2/a+5 B.-b^2/4a+5 C.2002 D.5

Axisymmetry of point a and point B about parabola
The axis of symmetry is x = (x1 + x2) / 2
X1 + X2, 0, equidistant from the axis of symmetry
So when x = X1 + X2, the value of quadratic function is C
Is C = 5 in the original question?

Three seven times five eight plus eight eleven times three seven minus three seven

Three out of seven
3/7（5/8+8/11-1）=3/7 * 207/88

Junior high school mathematics knowledge; why "the sum of efficiency when a and B work separately" is equal to the efficiency when they work together

For example, if the efficiency of a is 3 parts a day and that of B is 5 parts a day, then the sum of their efficiency is 8 parts a day. If they work separately, it's also 3 parts a plus 5 parts B or 8 parts a day. I think you don't understand. Maybe it's because they don't give you specific efficiency, but they set an unknown number, which is generally regarded as 1, so you don't know

The result of calculating a divided by a of B multiplied by B of a is to ask God to answer

A △ a of B × B of a
=A × a of B × a of B
=Square B of a

1. Xiaoying finished reading an anthology of mini fiction in three days. On the first day, she read more than a quarter of the whole book and six pages. On the second day, she read half of the whole book. On the third day, she read two-thirds of the first day. How many pages are there in this book?
2. ABC three numbers, a is four eleventh of the total number of BC, B is half of the total number of AC, C is 12, find the sum of ABC three numbers

1. On the third day, I read two-thirds of the first day. On the third day, I read 1 / 6 more than 4 pages of the whole book, so I read 5 / 12 more than 10 pages of the whole book on the first day + the third day, so the whole book has 10 / (1 / 2-5 / 12) = 120 pages. 2. A = 4 (B + C) / 11 = 4 (B + 12) / 11b = (a + C) / 2 = (a + 12) / 2, so a = 4 (B + 12) / 11 = 4 ((a + 12) / 2 + 12) /

Is it cold from 6 to 14 degrees
Temperature, wear thin will be cold

Generally speaking, you will feel very cold, because the temperature of the human body is between 36 and 37, so a larger temperature difference will make you feel colder, not to mention your thin clothes

If x = - 1, y = 2 and x = 2, y = - 1 are two solutions of the equation MX + NY = 10, M + n=

Substituting into the equation MX + NY = 10, we can get ① - M + 2n = 10, ② 2m-n = 10, ① plus ② to get m + n = 20