1)

a) 2x + 5 = 3⁴ : 3²

2x + 5 = 3²

2x + 5 = 9

2x = 9 - 5

2x = 4

x = 4 : 2

x = 2

b) (3x - 24).73 = 2.74

(3x - 24).73 = 148

3x - 24 = 148/73

3x = 148/73 + 24

3x = 1900/73

x = 1900/73 : 3

x = 1900/219

c) [3.(42 - x)] + 15 = 23.3

126 - 3x + 15 = 69

141 - 3x = 69

3x = 141 - 69

3x = 72

x = 72 : 3

x = 24

d) 126 + (132 - x) = 300

132 - x = 300 - 126

132 - x = 174

x = 132 - 174

x = -42

2)

a) 120 - (x + 55) = 60

x + 55 = 120 - 60

x + 155 = 60

x = 60 - 55

x = 5

b) (7x - 11).3 = 25.52 + 200

(7x - 11).3 = 1500

7x - 11 = 1500 : 3

7x - 11 = 500

7x = 500 + 11

7x = 511

x = 511 : 7

x = 73

c) 2x + 2x + 4 = 544

4x = 544 - 4

4x = 540

x = 540 : 4

x = 135

Chia câu hỏi ra đk bn 

Vầy ai giải nổi khó hỉu lắm

Đây là bài thực hiện phép tính nha mấy bạn(tính nhanh nếu có thể)

a. 4 x 126 x 25

= (4 x 25) x 126

= 100 x 126

= 12600

b. (9 x 8 – 12 – 5 x 12) x ( 1 + 2 + 3 + 4 + 5)

= (72 – 12 – 60) x ( 1 + 2 + 3 + 4 + 5)

= 0 x ( 1 + 2 + 3 + 4 + 5)

= 0

S=5+5^2+5^3+....+5^96= 
= 5+5^2+5^3+ 5^4+5^5+5^6....+ +5^91 + 5^92+5^93 +5^94 +5^95 +5^96 
=(5+5^2+5^3+ 5^4+5^5+5^6)(1+5^6 + ... +5^90)= 
=5* 126*31*(1+5^6 + ... +5^90)= 5* 126*31*(1+5^4 + ... +5^90) chia hết cho 126 

Bạn gộp 6 số lại là được 

a) \(5^{x+3}+5^x=126\)

\(\Rightarrow5^x\cdot\left(5^3+1\right)=126\)

\(\Rightarrow5^x\cdot\left(125+1\right)=126\)

\(\Rightarrow5^x=\dfrac{126}{126}\)

\(\Rightarrow5^x=1\)

\(\Rightarrow5^x=5^0\)

\(\Rightarrow x=0\)

b) \(\dfrac{9-3x}{2}=\dfrac{5-2x}{3}\)

\(\Rightarrow\dfrac{3\cdot\left(9-3x\right)}{6}=\dfrac{2\cdot\left(5-2x\right)}{6}\)

\(\Rightarrow3\cdot\left(9-3x\right)=2\cdot\left(5-2x\right)\)

\(\Rightarrow27-9x=10-4x\)

\(\Rightarrow-4x+9x=27-10\)

\(\Rightarrow5x=17\)

\(\Rightarrow x=\dfrac{17}{5}\)

c) \(7-4\left(x+1\right)=5\)

\(\Rightarrow4\left(x+1\right)=7-5\)

\(\Rightarrow4\left(x+1\right)=2\)

\(\Rightarrow x+1=\dfrac{1}{2}\)

\(\Rightarrow x=\dfrac{1}{2}-1\)

\(\Rightarrow x=-\dfrac{1}{2}\)

câu a x =2/3

câu b x=-90

a, x-1/4=5/8 . 2/3 

 \(x-\frac{1}{4}=\frac{5}{12}\)

x = \(\frac{5}{12}+\frac{1}{4}\)

x = \(\frac{2}{3}\)

b, x/126= -5/4 .4/7

\(\frac{x}{126}=\frac{-5}{7}\)

=> x .7 = (-5) . 126

=> x . 7 = -630

=> x = (-630) :7

=> x = -90

Học tốt

a,

b,

Ai giúp mình làm bài này với. Mình cảm ơn nhiều.

a) 153^2+99.153+47^2

= 153^2+2.47.153+47^2

= (153+47)^2

=200^2

=40000

b) 126^2-152.126+5776

= 126^2-2.76.126+76^2

= (126-76)^2

= 50^2

= 2500

c)3^8.5^8-(15^4-1).(15^4+1)

= 15^8-[(15^4)^2-1^2]

= 15^8-15^8+1

=1

d) (2+1).(2^2+1).(2^4+1)...(2^32+1)+1

= 1.(2+1).(2^2+1).(2^4+1)...(2^32+1)+1

= (2-1).(2+1).(2+1).(2^4+1)...(2^32+1)+1

= (2^2-1).(2^2+1).(2^4+1)...(2^32+1)+1

= (2^4-1).(2^4+1)...(2^32+1)+1

= (2^8-1)...(2^32+1)+1

= (2^32-1).(2^32+1)+1

= 2^64-1+1

= 2^64