Subtract 2 / 5 of what number from 125, the difference is 5, find this number? (use equation)

Subtract 2 / 5 of what number from 125, the difference is 5, find this number? (use equation)

Let this number be X
125-2/5x=5
2/5x=120
x=300

125 minus 2 / 3 of a number, the difference is 1 / 3 of 15. How many equation solutions is this book

125-(2/3)x=15×(1/3)
125-(2/3)x=5
(2/3)x=120
x=180

250 minus three eighths of a number, the difference is one third of 75. What's the number? (equation)

250 - three eighths x = 75X one third
250 - three eighths x = 25
Three eighths x + 25 = 250
Three eighths x = 250-25
Three eighths x = 225
x=600

Let 34 plus 5 of a number be equal to double minus 9. Let X be a number and the equation be___ ．

Let a certain number be x, then its 34 should be 34x and its double should be 2x. According to the series equation of equivalency relation, it is: 34x + 5 = 2x-9

A number plus 3 and 5 / 18, and then minus 1.75, the result is 2 and 4 / 9. What's the number? (use equation solution)

X + 3 and 5 / 18-1.75 = 2 and 4 / 9
x+59/18-7/4=22/9
x=22/9+7/4-59/18
x=88/36+63/36-118/36
x=11/12

5 times of a number minus 1 / 2 of it is 9. To find a number, use the equation

5x-0.5x=9
4.5x=9
x=2

5 / 7X + 3 = (x + 3) * 4 / 5
I can't work it out=

5/7X+3=（X+3）*4/5
5/7X+3=4/5x+12/5
5/7x-4/5x=12/5-3
-3/35x=-3/5
x=7

The solution of (3 / 7X + 66) △ 5 = (4 / 7x-66) △ 3

(3/7x+66)÷5=(4/7x-66)÷3
Multiply both sides by 15 to get
3(3/7x+66)=5(4/7x-66)
9/7x+198=20/7x-330
11/7x=528
x=336

The solution of x-20% - (2 / 7X + 2) = 3 / 5x + 5

X-1/5-2/7X-2=3/5X+5
X-2/7X-3/5X=5+2+1/5
X=9/5

Solution equation: 2 (x2-7x) 2-21 (x2-7x) + 10 = 0
There must be a process, a quadratic equation of one variable

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