Solution equation: 8x / 2 = 15

Solution equation: 8x / 2 = 15

Hello:
8x/2=15
8x=15×2
8x=30
x=30÷8
x=3.75

8x-0.6 = 9.4 * 2 to solve the equation

8x-0.6=9.4×2
8x-0.6=18.8
8x=18.8+0.6
8x=19.4
x=19.4÷8
x=2.425

8x + 3x0.9 = 6.3

8Ⅹ+2.7=6.3
8Ⅹ+2.7-2.7=6.3-2.7
8Ⅹ=3.6
Ⅹ=3.6÷8
Ⅹ=0.45

Given that the calculated results of (x + 1) (X & # 178; + MX + n) do not contain X & # 178; and X terms, find the values of M and n

（X+1）（X²+MX+N）
=x³+mx²+nx+x²+mx+n
=x³+(m+1)x²+(m+n)x+n
∵ the calculation results do not contain x &# 178; and X terms
∴{m+1=0
m+n=0
∴m=-1,n=1

In a circuit with constant voltage, when the resistance increases by 5 Ω, the current becomes 4 / 5 of its original value, then the original resistance is? Ω
1 / 3, then a? Ω resistor should be connected in series (write down the thinking process!)

In order to reduce the current, a resistor should be connected in series. The original resistance is r, the voltage is constant, and the current is used as a bridge. If the original current is I, the current after the resistance is increased by 5 Ω is 4I / 5. Solve the equations. U / R = IU / (R + 5) = 4I / 5u / (R + 5) = 4 * (U / R) / 5R = 20 Ω, U / 25 = IU / (25 + R1) = I / 3U / (25 + R1) = (U / 25)

Negative quarter of 2008 times negative one of 2009 times 4 of 2010

（－1/4）^2008=4^（-2008）
So the original formula = 4 ^ (- 2008) * 4 ^ 2010 * (- 1) ^ 2009
=4^2*(-1)
=-16

A student measures the power of the TV set according to the "3000r / kWh" on the electric energy meter. When only the TV set is turned on, record in 7.5min, and the dial turns around for 30 weeks, what is the power of the TV set?

3000r / kWh: it means that the electric energy meter is 1kwh per 3000 cycles, because it takes 30 weeks in 7.5min, that is, it takes 0.01kwh in 7.5min, that is, it takes 0.125h in 7.5min
According to the following formula:
P＝0.01kWh/0.125h=0.08kW
P＝0.08kW*1000=80W
So the power of the TV is 80W

Factorization factor 5 (2a-1) & #178; - 2A + 1

5( 2a - 1 )" - 2a + 1
= 5( 1 - 2a )" + ( 1 - 2a )
= ( 1 - 2a )( 5 - 10a + 1 )
= ( 1 - 2a )( 6 - 10a )
= 2( 3 - 5a )( 1 - 2a )
perhaps
= 5( 2a - 1 )" - ( 2a - 1 )
= ( 2a - 1 )( 10a - 5 - 1 )
= ( 2a - 1 )( 10a - 6 )
= 2( 5a - 3 )( 2a - 1 )

A 1.8-meter-long rectangular copper bar with a cross-section of 5 cm on each side. If the copper bar weighs 8.9 kg per cubic decimeter, how many kg does the copper bar weigh?

Solution: 1.8m = 18decimeter, 5cm = 0.5decimeter, 18 × 0.5 × 0.5 × 8.9 = 4.5 × 8.9 = 40.05 (kg) answer: the total weight of this copper bar is 40.05kg

Simple calculation of 8.25 * 0.24 + 1.76

8.25*0.24+1.76
=8.25*4*0.06+1.76
=33*0.06+1.76
=1.98+1.76
=3.74