66,34 : a x 11,5 = 71,3

66,34 : a = 71,3 : 11,5 = 6,2

a = 66,34 : 6,2 = 10,7

a) 47 x 9 = 47 x (10 -1)

= 47 x 10 - 47 x 1 = 470 -47 = 423

24 x 99 = 24 x ( 100 -1)

= 24 x 100 - 24 x 1 = 2400 - 24 = 2376

b) 138 x 9 = 138 x (10 -1)

= 138 x 10 - 138 x 1 = 1380 - 138 = 1242

123 x 99 = 123 x (100 -1)

= 123 x 100 - 123 x 1 = 12300 - 123 = 12177

đung hết rồi

đề bài

Nếu tính

a ) 37 x 2 x 7 + 7 x 26 = 700

b ) 24 x 18 + 12 x 64 =1200

Bạn Cho yêu cầu của bài nhé. Chứ thế này mình ko hiểu

Đề đọc khó hiểu quá. Bạn nên gõ đề bằng công thức toán (biểu tượng $\sum$ góc trái khung soạn thảo) để mọi người hiểu đề của bạn hơn nhé.

a: -26-(x-7)=0

=>x-7=-26

=>x=-26+7=-19

b: \(24-\left(30+x\right)=-7\)

=>\(30+x=24-\left(-7\right)\)

=>\(x+30=24+7=31\)

=>x=31-30=1

c: \(3-\left(17-x\right)=-12\)

=>\(17-x=3-\left(-12\right)\)

=>\(17-x=3+12=15\)

=>x=17-15=2

d: \(\left(5-x\right)-7=-15\)

=>\(5-x=-15+7=-8\)

=>\(x=5-\left(-8\right)=5+8=13\)

a) \(96-7\left(x+1\right)=14^4:14^3\)

\(\Rightarrow96-7\left(x+1\right)=14^{4-3}\)

\(\Rightarrow96-7\left(x+1\right)=14\)

\(\Rightarrow7\left(x+1\right)=96-14\)

\(\Rightarrow7\left(x+1\right)=82\)

\(\Rightarrow x+1=\dfrac{82}{7}\)

\(\Rightarrow x=\dfrac{82}{7}-1\)

\(\Rightarrow x=\dfrac{75}{7}\)

b) \(\left(5x+3^4\right)\cdot2^4=2^6\cdot7^2\)

\(\Rightarrow5x\cdot2^4+3^4\cdot2^4=2^6\cdot7^2\)

\(\Rightarrow5x\cdot2^4+6^4=\left(2^3\cdot7\right)^2\)

\(\Rightarrow80x+1296=3136\)

\(\Rightarrow80x=1840\)

\(\Rightarrow x=\dfrac{1840}{80}\)

\(\Rightarrow x=23\)

a: =>96-7(x+1)=14

=>7(x+1)=82

=>x+1=82/7

=>x=75/7

b =>5x+81=2^2*7^2=196

=>5x=115

=>x=23

a) \(96-7\left(x+1\right)=14^4:14^3\\ \Leftrightarrow96-7\left(x+1\right)=14\\ \Leftrightarrow7\left(x+1\right)=82\\ \Leftrightarrow x+1=\dfrac{82}{7}\\ \Leftrightarrow x=\dfrac{75}{7}\)

b) \(\left(5x+3^4\right)\cdot2^4=2^6\cdot7^2\\\Leftrightarrow5x+81=196\\ \Leftrightarrow5x=115\\ \Leftrightarrow x=23 \)

= (26/50+24%+0,02x12)x(1/4-1/4)

=(26/50+24%+0,02x12)x0

=0

\(A=\frac{x^{24}+x^{20}+x^{16}+....+x^4+1}{x^{26}+x^{24}+x^{22}+.....+x^2+1}\) (1)

Ta có \(x^{26}+x^{24}+x^{22}+...+x^2+1\)

\(=\left(x^{26}+x^{22}+x^{18}+....+x^2\right)+\left(x^{24}+x^{20}+...+x^4+1\right)\)

\(=x^2\left(x^{24}+x^{20}+.....+x^4+1\right)+\left(x^{24}+x^{20}+...+x^4+1\right)\)

\(=\left(x^2+1\right)\left(x^{24}+x^{20}+x^{16}+....+x^4+1\right)\) (2)

Từ (1),(2) ta có \(A=\frac{x^{24}+x^{20}+x^{16}+...+x^4+1}{\left(x^2+1\right)\left(x^{24}+x^{20}+x^{16}+....+x^4+1\right)}=\frac{1}{x^2+1}\)

Vậy A=\(\frac{1}{x^2+1}\)

a) Ta có: \(\left(4x-1\right)^2=\left(1-4x\right)^2\)

\(\Leftrightarrow\left(4x-1\right)^2-\left(1-4x\right)^2=0\)

\(\Leftrightarrow\left(4x-1-1+4x\right)\left(4x-1+1-4x\right)=0\)

\(\Leftrightarrow0\cdot x=0\)(luôn đúng)

Vậy: \(x\in R\)

b) Ta có: \(\dfrac{x-100}{24}+\dfrac{x-98}{26}+\dfrac{x-96}{28}=3\)

\(\Leftrightarrow\dfrac{x-100}{24}-1+\dfrac{x-98}{26}-1+\dfrac{x-96}{28}-1=0\)

\(\Leftrightarrow\dfrac{x-124}{24}+\dfrac{x-124}{26}+\dfrac{x-124}{28}=0\)

\(\Leftrightarrow\left(x-124\right)\cdot\left(\dfrac{1}{24}+\dfrac{1}{26}+\dfrac{1}{28}\right)=0\)

mà \(\dfrac{1}{24}+\dfrac{1}{16}+\dfrac{1}{28}>0\)

nên x-124=0

hay x=124

Vậy: x=124