20 is 2.4 less than 8 times of a number. Find the number

20 is 2.4 less than 8 times of a number. Find the number

Let this number be X
8x-2.4=20
8x=20+2.4
8X=22.4
x=2.8

If f (x) = 2x ^ 2-mx + 3 is a decreasing function on (- ∞, - 2) and an increasing function on [- 2, + ∞), then f (1)=

The axis of symmetry is x = m / 4 = - 2
,m=-8
f(1)=2+8+3=13

How much is thirty-three divided by eleven games on the second day of the twentieth day

30

How to prove that an empty set is a subset of any set?
How to prove that an empty set is a subset of any set

Any set includes an empty set. An empty set is a proper subset of any non empty set!

Given that the solution of equation 5x-2 (x-1) = x-2m is x = 3, find the value of M

5x-2(x-1)=x-2m
5x3-2(3-1)=3-2m
15-4=3-2m
2m=3-11
2m=-8
m=-4

Just use the number 8 to make up five numbers and fill in the box below to make the formula true______ ﹢______ ﹢______ ﹢______ ﹢______ =1000．

According to the stem analysis can be: 888 + 88 + 8 + 8 + 8 = 1000, so the answer is: 888; 88; 8; 8; 8

The difference between 5 and X is 13 times greater than 2 times of X. The equation of 1 is as follows:______ ．

13 (5-x) is the difference between 5 and X, and 2 times of X is 2x

cos23°cos22°-sin23°sin22°=

Original formula = cos (23 ° + 22 °) = cos45 ° = √ 2 / 2

2.5 times of a number, 5 / 8 of 20 is less than 12. How much is this number? (use equation solution)

Hello
Let this number be X
2.5x+12=20*5/8
2.5x=12.5-12
2.5x=0.5
x=0.5÷2.5
x=0.2
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The earliest way to divide a month into four weeks, with seven days as a week is as follows:

Babylonians