5:

a: Chiều rộng là 18*1/6=3m

S=18*3=54m²

Số viên gạch cần mua là:

54*10^4:30^2=600 viên

b: Số viên gạch phải giảm đi là:

600*5/6=500 viên

a: \(\widehat{B}=\dfrac{180^0-80^0}{2}=50^0\)

b: Chiều dài là \(\sqrt{15^2-9^2}=12\left(dm\right)\)

X x ( 6,2 + 3,8 ) = 24,38

X x 10 = 24,38 

X = 2,438

6,2 x X +X x 3,8=43,18-18,8

X x(6,2+3,8)=25

X x 10=25

X =25:10

X=2,5

vậy X = 2,5

mikthaays bạn hương làm tắt quá ạ

1 poverty

2 decision

3 worried

4 awake

5 singers

7 northen

8 disappeared

9 difference

10 unimportant

11 windy

12 portable

13 sensibly

14 painting

15 mainly

SOS😥👉🏳👈

\(1500-\left\{5^3\cdot2^3-11\left[7^2-5\cdot2^3+8\left(11^2-121\right)\right]\right\}\\ =1500-\left[125\cdot8-11\left(49-5\cdot8+8\cdot0\right)\right]\\ =1500-\left[125\cdot8-11\left(49-40+0\right)\right]\\ =1500-\left(125\cdot8-11\cdot9\right)\\ =1500-\left(1000-99\right)\\ =1500-901\\ =599\)

sau số 11 có đấu j bạn

sau số 11 là x bạn nhé   Nguyễn Long Thành

Các bạn chỉ cần giúp mik câu c ạ

\(C=\dfrac{x^3}{x^2-4}-\dfrac{x}{x-2}+\dfrac{2}{x+2}\)

\(=\dfrac{x^3-x\left(x+2\right)+2\left(x-2\right)}{x^2-4}\)

\(=\dfrac{x^3-x^2-2x+2x-4}{x^2-4}\)

\(=\dfrac{x^3-x^2-4}{x^2-4}\)

a,\(C=\dfrac{x^3}{x^2-4}-\dfrac{x}{x-2}-\dfrac{2}{x+2}\)

\(\Rightarrow C=\dfrac{x^3}{\left(x-2\right)\left(x+2\right)}-\dfrac{x\left(x+2\right)}{\left(x-2\right)\left(x+2\right)}-\dfrac{2\left(x-2\right)}{\left(x-2\right)\left(x+2\right)}\)

\(\Rightarrow C=\dfrac{x^3}{\left(x-2\right)\left(x+2\right)}-\dfrac{x^2+2x}{\left(x-2\right)\left(x+2\right)}-\dfrac{2x-4}{\left(x-2\right)\left(x+2\right)}\)

\(\Rightarrow C=\dfrac{x^3-x^2-2x-2x+4}{\left(x-2\right)\left(x+2\right)}\)

\(\Rightarrow C=\dfrac{x^3-x^2-4x+4}{\left(x-2\right)\left(x+2\right)}\)

\(\Rightarrow C=\dfrac{x^2\left(x-1\right)-4\left(x-1\right)}{\left(x-2\right)\left(x+2\right)}\)

\(\Rightarrow C=\dfrac{\left(x^2-4\right)\left(x-1\right)}{\left(x-2\right)\left(x+2\right)}\)

\(\Rightarrow C=\dfrac{\left(x-2\right)\left(x+2\right)\left(x-1\right)}{\left(x-2\right)\left(x+2\right)}\)

\(\Rightarrow C=x-1\)

b, C=0\(\Rightarrow x-1=0\Rightarrow x=1\)

c, Để C nhận giá trị dương thì \(x-1\ge0\Rightarrow x\ge1\)

Em cần hỗ trợ câu nào em nhỉ?

\(3n-2\inƯ\left(15\right)\) \(=\left\{1;-1;3;-3;5;-5;15;-15\right\}.\)

\(\Leftrightarrow n\in\left\{1;\dfrac{1}{3};\dfrac{5}{3};\dfrac{-1}{3};\dfrac{7}{3};-1;\dfrac{17}{3};\dfrac{-13}{3}\right\}.\)

Mà \(n\ne\dfrac{2}{3};n\in Z.\)

\(\Rightarrow n\in\left\{1;-1\right\}.\)