If the solution of the linear equation of one variable - KX = k is x = - 1, the following condition must be satisfied?

If the solution of the linear equation of one variable - KX = k is x = - 1, the following condition must be satisfied?

The necessary condition is k ≠ 0
If k = 0, then x can be any value, which does not conform to the title
Hope to adopt, thank you!

If (K-2) x * x + KX-5 = 0 is a linear equation of one variable, then K=_____ ,x=_____

Because "once per dollar", so K-2 = 0, so k = 2
So 2x-5 = 0, so x = 2.5

As shown in figure a, when the power supply voltage is 9 V, the maximum resistance of the sliding rheostat is 100 Ω, and the current is between 0.1 A and 0.4 a, the electronic components can work normally. If the relationship between the current passing through the electronic component and the voltage at both ends is shown in figure B, the following judgment is correct ()
A. When the electronic components work, the resistance remains unchanged. B. when the electronic components are in normal working state, the minimum power consumed by the circuit is 3.6 watts. C. when p is in the middle point, the voltage ratio of the electronic components to the sliding rheostat is 1:1d. In order to make the electronic components in normal working state, the resistance range of the sliding rheostat should be controlled within 12.5 ~ 70 Ω

It can be seen from the image that the resistance of the electronic component is changing, so a is wrong. When the power consumed by the circuit is the minimum, the circuit current is the minimum, I small = 0.1A, the minimum power consumed by the circuit P = UI small = 9V × 0.1A = 0.9W, so B is wrong. Because the electronic component is connected in series with the sliding rheostat, the current passing through is equal, so the voltage ratio at both ends of the electronic component and sliding rheostat is equal The minimum circuit current is 0.1A, and the minimum voltage at both ends of the electronic component is 2V, so the maximum voltage at both ends of the sliding rheostat is U1 = 9v-2v = 7V, and the resistance of the sliding rheostat connected to the circuit is the largest, R large = u1i small = 7v0.1a = 70 Ω, The maximum current of the circuit is 0.4A, and the maximum voltage at both ends of the electronic components is 4V. Therefore, the minimum voltage at both ends of the sliding rheostat is U2 = 9v-4v = 5V, and the resistance of the sliding rheostat connected to the circuit is the minimum, R small = u2i large = 5v0.4a = 12.5 Ω. Therefore, the resistance range of the sliding rheostat should be controlled within 12.5 ~ 70 Ω

What is the formula of Newton's second law

F=ma

The area of a triangle is 17cm and its height is 5cm. What is the length of its bottom?
The sum of the top and bottom of a trapezoid is 36dm and its height is 9dm. What is its area?

According to area = bottom x height △ 2
Bottom = 2x17 △ 5 = 34 △ 5 = 6.8 (CM)

As shown in the figure, the object with mass of M = 0.1kg is fixed in the elevator with two identical vertical springs. When the elevator accelerates upward with the acceleration of 4m / S2, the tension of the upper spring on the object is 0.4N; when the elevator and the object both move upward with the acceleration of 8M / S2, the tension of the upper spring is ()
A. 0.6NB. 0.8NC. 1.0ND. 1.2N

According to Newton's second law, F1 + F2 mg = MA1, F2 = 1.0N. When the elevator and the object are moving upward at the acceleration of 8m / S2, the resultant force F = ma2 = 0.8N

Mixed operation of rational multiplication and division

-5+21*8/2-6-59 68/21-8-11*8+61 -2/9-7/9-56 4.6-(-3/4+1.6-4-3/4) 1/2+3+5/6-7/12 [2/3-4-1/4*(-0.4)]/1/3+2 22+(-4)+(-2)+4*3 -2*8-8*1/2+8/1/8 (2/3+1/2)/(-1/12)*(-12) (-28)/(-6+4)+(-1) 2/(-2)+0/7-(-8)*(-2)...

Why is power equal to torque times angular velocity

We know that power P = work w △ time t, work w = force F × distance s, so p = f × s / T = f × velocity v
Here V is the linear velocity, and in the engine, the linear velocity of the crankshaft = the angular velocity of the crankshaft, w × the radius of the crankshaft, R. substituting the above formula, we can get: power P = force, f × radius, R × angular velocity, W; and force, f × radius, r = torque
It is concluded that power P = torque × angular velocity ω

It is known that the sum of the first n terms of the arithmetic sequence {an} is Sn, the tolerance D ≠ 0, A1 = 1, and A1, A2, a7 are proportional sequences. (1) find the sum of the first n terms of the sequence {an} and Sn; (2) let BN = 2sn2n − 1, the sum of the first n terms of the sequence {BN} be TN, and prove that 2tn-9bn-1 + 18 ＞ 64bn (n + 9) BN + 1 (n > 1)

(1) ∵ A1, A2, a7 are in equal proportion sequence, ∵ A22 = A1 · A7, that is, (a1 + D) 2 = A1 (a1 + 6D), A1 = 1, D ≠ 0, ∵ d = 4. ∵ Sn = Na1 + n (n − 1) 2D = n + 2n (n-1) = 2n2-n

When a trolley bus starts to drive at a speed of 20 m / s with an acceleration of 2.5 m / S2, what is its instantaneous speed at the end of 4.0 s?
What about the displacement of the tram after 12 seconds?

v=v0+at=20-2.5*4=10m/s