If a solution of the equation 2x + y = 0 is x = a, y = B, then the value of 6A + 3B + 2 is

If a solution of the equation 2x + y = 0 is x = a, y = B, then the value of 6A + 3B + 2 is

6a+3b+2
=6x+3y+2
=3(2x+y)+2
=3*0+2
=2

If {x = a, y = B is the solution of the equation 2x + y = 0, what is the value of 6A + 3B + 2
Answer with the knowledge of grade seven

2x+y=o,
2a+b=o
6a+3b+2=3(2a+b)+2=0+2=2

Special solution of differential equation y '' - 2Y '+ y = Xe ^ x

Characteristic equation R ^ 2-2r + 1 = 0
r=1
Y '' - 2Y '+ y = 0 general solution y = C1E ^ x + c2xe ^ x
Y '' - 2Y '+ y = Xe ^ x special solution y = C (x) e ^ x
y'=C'e^x+Ce^x
y''=C''e^x+2C'e^x+Ce^x
C''+2C'+C-2C'-2C+C=x
C''=x
C '= (1 / 2) x ^ 2 + m (constant)
C = (1 / / 6) x ^ 3 + MX (m constant)
Therefore, the general solution of Y '' - 2Y '+ y = Xe ^ x is y = C1E ^ x + c2xe ^ x + (1 / 6) x ^ 3 * e ^ X

If a is not equal to 2 and B is not equal to - 1, what is the relationship between the value of M = a square plus b square minus 4A plus 2B and - 5?

M>-5
It is proved that M = a * a + b * b-4a + 2B
=(a-2)*(a-2)+(b+1)(b+1)-5
Because: A is not equal to 2, B is not equal to - 1, so m > - 5

Vertical calculation of 7.05 △ 0.94

If [1 + x] + [1 + x] ^ 2 + [1 + x] ^ 3 +. + [1 + x] ^ n = A0 + A1 * x + A2 * x ^ 2 + a3 * x ^ 3 +. An * x ^ n, and a1 + A2 + a3 +. + an-1 = 29-n, what is n

When x = 1, [1 + x] + [1 + x] ^ 2 + [1 + x] ^ 3 +. + [1 + x] ^ (n-1)
=a0+a1+a2+a3+.+an-1=2+2^2+2^3+…… +2^(n-1)=2^n-2
When x = 0, [1 + x] + [1 + x] ^ 2 + [1 + x] ^ 3 +. + [1 + x] ^ (n-1) = A0 = 1 + 1 + +1=n-1
So a1 + A2 + a3 +. + an-1 = (29-n) - A0
So there's no problem with your data, right?

7.6-7x-x=3.6

7.6-7x-x=3.6
-8X=-4.0
X=0.5

A barrel of oil is 180 kg in a barrel. After half of the sales, there are still 100 grams in a barrel. How many grams of oil and barrel?

A barrel of oil is 180 kg in a barrel. After half of the sale, there is still 100 kg in a barrel. How many kg of oil and barrel are there
A barrel of oil is 180 kg in a barrel. After half of the sales, there are still 100 kg in a barrel,
Oil sold = 180-100 = 80kg
Then the original oil = 80 * 2 = 160 kg
Barrel weight = 180-160 = 20kg

The continuity and differentiability of function at x = 0 are discussed
F (x) = x sin 1, X is not equal to 0
0 ,x=0

When x = 0, f (x) is continuous. When x approaches 0, sin (1 / x) is bounded, X is infinitesimal, and multiplication is 0, so it is continuous;
As for the derivative, you can calculate the left derivative and the right derivative, that is, the derivative at x0, and see if x is equal when it approaches 0. It should be non differentiable. You can calculate it

C language, about comma expression
Comma expression "(a = 3 * 5, a * 4), the value of" a + 5 "is 20: = 3 * 5, get a = 15; then find a * 4 = 60; finally find a + 5 = 20, so the value of comma expression is 20. Is this explanation correct? Why is it not equal to 80?

The value of this expression should be 20, and the value of the comma expression should be the value on the right side of the comma. For a = 3 * 5, a * 4, a is assigned 15 on the left side, so a * 4 = 60 on the right side is the value of this expression, but there is no assignment to a, so the value of a is still 15. For the whole expression, its value should be a + 5, because in the previous expression