Where will Sarah leave in December?

How many new words should students learn by heart per day?

How much does your new watch cost?

Whose bag is this?

Who does this bag belong to?

the same height as me

the same as mine

old as her

The flowers need to be watered

The flowers need watering

The house doesn't need to be painted

The house doesn't need painting

Đặt x/3=y/2=k

=>x=3k; y=2k

Ta có: xy=96

=>k²=16

Trường hợp 1: k=4

=>x=12; y=8

TH2: k=-4

=>x=-12; y=-8

Đặt x/3=y/4=k

=>x=3k; y=4k

Ta có: $x^2+y^2=400$

$\iff 25k^2=400$

$\Rightarrow k^2=16$

Trường hợp 1: k=4

=>x=12; y=16

Trường hợp 2: k=-4

=>x=-12; y=-16

Câu 5: 

a: $32<2^x<128$

=>2^x=64

=>x=6

b: $2\cdot 16>=2^x>4$

=>5>=x>2

hay $x\in \left\{3;4;5\right\}$

d: $\iff {\left(x-1\right)}^2=25-9=16$

=>x-1=4 hoặc x-1=-4

=>x=5 hoặc x=-3

a, 461 + ( - 461) + 40 + (- 78) = 40 + (- 40 - 28) = 40 + (- 40) + ( -28) = -28

b, 53 + (- 76)+ 76 + ( - 53) = (- 76) + 76 + 53 + (- 53) = 0

c, (- 564) + 564 + (-724) + 224 = (- 500 - 224 ) + 224 = (- 500) + (-224) + 224 = -500

d, - 87 + ( -12) + 487 + 512 = (- 87) + 87 + 400 + (-12) + 12 + 500 = 400 + 500 = 900

a, $2x=55\iff x=\frac{55}{2}$

b, $x=100-150=-50$

c, $x+33=71-26=45\iff x=45-33=12$

d, $x+73=102\iff x=102-73=29$

e, $x+41=100\iff x=100-41=59$

f, => x - 9 = 0 <=> x = 9 

g, => x - 1 = 1 <=> x = 2 

h, $2^x=2^5\Rightarrow x=5$

=14x−2⋅49=14x−98