Ta có:

p + n + e = 49

2p + n = 49 (Nguyên tử trung hòa về điện)

\(n=\frac{53,125}{100}p=\frac{17}{32}p\)

\(\rArr p=49:\left(17+32\right)\times32\) ≃ \(32\)

Vậy số proton của X là: 32

Mình nhầm, số p phải chia 2 nữa là: 32 : 2 = 16 nhé :)))

bạn thêm ở phần n = 53,125/100 x 2p = 17/32 x 2p với phép tính ở dưới nhé. Xin lỗi bạn nhiều.

\(14\times7^{2021}=35\times7^{2021}-3\times49^{x}\)

\(35\times7^{2021}-14\times7^{2021}=3\times7^{2x}\)

\(21\times7^{2021}=3\times7^{2x}\)

\(3\times7^{2022}=3\times7^{2x}\)

\(7^{2022}=7^{2x}\)

\(2022=2x\)

\(x=2022:2\)

\(x=1011\)

Vậy \(x=1011\)

Olm chào em, hiện tại câu hỏi của em chưa hiển thị đấy có thể là do file mà em tải lên bị lỗi nên đã không hiển thị trên diễn đàn. Em nên viết đề bài trực tiếp trên Olm. Như vậy em sẽ không mắc phải lỗi file đề. Điều này giúp em nhanh chóng nhận được sự trợ giúp từ cộng đồng olm. Cảm ơn em đã đồng hành cùng Olm.

14 x 7\(^{2021}\) = 35 x 7\(^{2021}\) - 3 x \(49^{x}\)

3 x 49\(^{x}\) = 35 x 7 \(^{2021}\) - 14 x \(7^{2021}\)

3 x 49\(^{x}\) = 7\(^{2021}\) x (35 - 14)

3 x 49\(^{x}\) = 7\(^{2021}\) x 21

49\(^{x}\) = 7\(^{2021}\) x 21 : 3

49\(^{x}\) = 7\(^{2021}\) x (21 : 3)

49\(^{x}\) = 7\(^{2021}\) x 7

49\(^{x}\) = 7\(^{2022}\)

(7\(^2\))\(^{x}\) = 7\(^{2022}\)

7\(^{2x}\) = 7\(^{2022}\)

2\(x\) = 2022

\(x\) = 2022 : 2

\(x\) = 1011

Vậy \(x=1011\)

Ta có: \(\left(x-5\right)^7=\left(x-5\right)^9\)

=>\(\left(x-5\right)^9-\left(x-5\right)^7=0\)

=>\(\left(x-5\right)^7\cdot\left\lbrack\left(x-5\right)^2-1\right\rbrack=0\)

=>\(\left(x-5\right)^7\cdot\left(x-5-1\right)\left(x-5+1\right)=0\)

=>\(\left[\begin{array}{l}x-5=0\\ \left(x-5\right)=1\\ x-5=-1\end{array}\right.\Rightarrow\left[\begin{array}{l}x=5\\ x=6\\ x=4\end{array}\right.\)

1. ✔

2. ✘ ➞ What about getting a cleaner to wash your clothes?

3. ✘ ➞ I don't like ironing, so I have a woman do it for me.

4. ✔

5. ✘ ➞ Why haven't you had your films developed yet?

1 to cut => cut

2 wash => to wash

3 to do => do

4 đúng

5 develop => developed

1. ✔

2. ✘ ➜ Have you had a meal prepared for you?

3. ✘ ➜ We are having the trees in the garden cut down.

4. ✘ ➜ Ron is going to have his house repainted after the summer vacation.

5. ✘ ➜ When are you going to have the curtain washed?

1 đúng

2 prepare => prepared

3 cutting => cut

4 repainted his house => his house repainted

5 wash => washed

1. ✔

2. ✘ ➜ Have you had a meal prepared for you?

3. ✘ ➜ We are having the trees in the garden cut down.

4. ✘ ➜ Ron is going to have his house repainted after the summer vacation.

5. ✘ ➜ When are you going to have the curtain washed?

1 đúng 2 prepare => prepared 3 cutting => cut 4 repainted his house => his house repainted 5 wash => washed