How about 35 + x = 3x + 15?

How about 35 + x = 3x + 15?

35+x=3x+15
3x-x=35-15
2x=20
x=10

How to calculate x (x-1) 1 / 2 + X (x + 1) 1 / 2 + ······· + (x + 9) (x + 10) 1 / 2 = 11 / 12?

X (x-1) 1 / 1 + X (x + 1) 1 / 1 + ······ + (x + 9) (x + 10) 1 / 1 = 1 / (x-1) - 1 / x + 1 / X-1 / (x + 1) +. 1 / (x + 9) - 1 / (x + 10) = 1 / (x-1) - 1 / (x + 10) = 11 / 1212 (x + 10-x + 1) = 11 (x-1) (x + 10) 12 * 11 = 11 (x-1) (x + 10) 12 = (x-1) (x + 10) x ^ 2 + 9x-22 = 0 (x + 11

15 to 5 / 9 for 12 to X
Proportion

15 to 5 / 9 for 12 to X
15x = 5 / 9 * 12
15x = 5 / 108
X = 5 / 108 △ 15
X = 1 / 324
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5 / 21 + 16 / 21 × 7 / 8 are calculated by simple method

5 / 21 + 16 / 21 × 7 / 8
=1/21x5+1/21x14
=1/21x(5+14)
=1/21x19
=19/21

(AX + by) + (BX ay) &# 178; factorization

The title should be as follows: (AX + by) & # 178; + (BX ay) & # 178; (AX + by) & # 178; + (BX ay) & # 178; original = (AX + by) & # 178; + (BX ay) & # 178; = (A & # 178; X & # 178; + B & # 178; Y & # 178; + 2axby) + (B & # 178; X & # 178; - 2axby + A & # 178

What's the product of 8 minus 3 / 1 divided by 9 / 4 and multiplying the difference by 2.4
The result is 16, the process is

The quotient of 3 / 1 divided by 9 / 4 = 4 / 9 △ 1 / 3 = 12 / 9 = 4 / 3
8-4 / 3 = 20 / 3
20 / 3 × 2.4 = 16
[8-(4/9)÷(1/3)]×2.4=[8-(4/3)]×2.4=(20/3)×2.4=16
The top two divide by

With a 52 cm long lead wire, a 6 cm, 4 cm wide and () cm high rectangular teaching aid can be welded
A. 2B. 3C. 4D. 5

(52-6 × 4-4 × 4) △ 4, = (52-24-16) △ 4, = 12 △ 4, = 3 (CM); therefore, B

Find the remainder of the product 15 × 38 × 412 × 541 divided by 13______ ．

15÷13=1… 2，38÷13=2… 12，412÷13=31… 9，541÷13=41… 8，2×12×9×8=1728，1728÷13=132… 12. A: the remainder of the product 15 × 38 × 412 × 541 divided by 13 is 12

Given the first n terms of sequence {an} and Sn = n2-9n, if 5 ＜ AK ＜ 8, then K=______ ．

When n = 1, A1 = S1 = 12-9 = - 8 is also suitable. The general formula of {an} is an = 2n-10. From 5 ＜ AK ＜ 8, we can get 5 ＜ 2k-10 ＜ 8, and the solution is 152 ＜ K ＜ 9, and K ∈ Z, so the answer is: 8

(1) one half of 4.5 is exactly 5% of X. what is x?
Formula and equation are OK,

4.5x1/2=5%x
x=45