a)=4.25x(58.47+41.53)-125

=4.25x100-125

=425-100

=325

Ngày thứ hai nhà máy sản xuất được số tấn đường là:

1,17-0,12= 1,05 (tấn)

Cả hai ngày thứ nhất và thứ hai, nhà máy sản xuất được số tấn đương là:

1,17+1,05=2,22 (tấn)

Ngày thứ ba nhà máy sản xuất được số tấn đường là:

4,14-2,22=1,92 (tấn)

"Chúc em học tốt."

Lời giải:

Đặt $\frac{a}{b}=\frac{c}{d}=k$

$\Rightarrow a=bk, c=dk$. Khi đó:

$\frac{a-b}{b}=\frac{bk-b}{b}=\frac{b(k-1)}{b}=k-1(1)$

$\frac{c-d}{d}=\frac{dk-d}{d}=\frac{d(k-1)}{d}=k-1(2)$

Từ $(1); (2)\Rightarrow \frac{a-b}{b}=\frac{c-d}{d}$

-------------------

$\frac{2a+3b}{2a-3b}=\frac{2bk+3b}{2bk-3b}=\frac{b(2k+3)}{b(2k-3)}=\frac{2k+3}{2k-3}(3)$

$\frac{2c+3d}{2c-3d}=\frac{2dk+3d}{2dk-3d}=\frac{d(2k+3)}{d(2k-3)}=\frac{2k+3}{2k-3}(4)$

Từ $(3); (4)\Rightarrow \frac{2a+3b}{2a-3b}=\frac{2c+3d}{2c-3d}$

Lời giải:

a. Với $n$ nguyên khác -3, để $B$ nguyên thì:

$2n+9\vdots n+3$

$\Rightarrow 2(n+3)+3\vdots n+3$

$\Rightarrow 3\vdots n+3$

$\Rightarrow n+3\in\left\{\pm 1; \pm 3\right\}$

$\Rightarrow n\in\left\{-2; -4; 0; -6\right\}$

b. 

$B=\frac{2n+9}{n+3}=\frac{2(n+3)+3}{n+3}=2+\frac{3}{n+3}$

Để $B_{\max}$ thì $\frac{3}{n+3}$ max

Điều này đạt được khi $n+3$ là số nguyên dương nhỏ nhất

Tức là $n+3=1$

$\Leftrightarrow n=-2$

c. Để $B$ min thì $\frac{3}{n+3}$ min

Điều này đạt được khi $n+3$ là số nguyên âm lớn nhất 

Tức là $n+3=-1$

$\Leftrightarrow n=-4$

Lời giải:
a. $2^3.8=2^3.2^3=2^6$

b. $5^2.25=5^2.5^2=5^4$

c. $27:3^2=3^3:3^2=3^1$

d. $4^2.16=4^2.4^2=4^4$
e. $5^3.5^6=5^9$

f. $3^4.3=3^5$

g.$3^5.4^5=(3.4)^5=12^5$
h. $8^5.2^3=(2^3)^5.2^3=2^{15}.2^3=2^{18}$

i. $a^3.a^5=a^8$

j. $x^7.x.x^4=x^{7+1+4}=x^{12}$

k. $5^6:5^3=5^3$
l. $3^{15}:3^3=3^{15-3}=3^{12}$

m. $4^6:4^6=4^0=1$
n. $9^8:3^2=(3^2)^8:3^2=3^{16}:3^2=3^{14}$

o. $a:a=a^0=1$
p. $5^8.5.5^2=5^{8+1+2}=5^{11}$
q. $4.4^3=4^4$
r. $3.3^4=3^5$

s. $36.6^5=6^2.6^5=6^7$

t. $2^5.2^3=2^8$

u. $3^{10}:3^3=3^7$

v. $2^{10}:2^3=2^7$

w. $5^8:25=5^8:5^2=5^6$
x. $16:2^3=2^4:2^3=2^1$
y. $4.2^3=2^2.2^3=2^5$
z. $2^{10}:4=2^{10}:2^2=2^8$

?

lỗi bn !

Lag Lag

went

drove

arrived - was

asked

said

told

walked

saw

stopped - bought

was

1, went
2, drove
3, arrived - was
4, asked - had
5, said
6, told
7, walked
8, saw
9, stopped - bought
10, was

1 went

2 drove

3 arrived/was

4 asked/had

5 said

6 told

7 walked

8 saw

9 stopped/bought

10 was

I went swimming yesterday.

Mrs. Nhung washed the dishes.

My mother went shopping with her friends in the park.

Nam and I studied hard last weekend.

My father played golf yesterday.

Last night, Phong listened to music for two hours.

They had a nice weekend.

I went swimming yesterday

Mrs. Nhung washed the dishes

My mother went shopping with her friends in the park

Lan cooked chicken noodles for dinner

Name and I studied hard last weekend

My father played golf yesterday

Last night, Phong listened to music for 2 hours

They had a nice weekend