a: Ta có: 5,7x15,3+26,7x15,3

=15,3x(5,7+26,7)

=15,3x32,4

=495,72

b: \(\left(3,5\times12,3+24,5\times12,3\right)\times\left(58\times11-5800\times0,01-580\right)\)

\(=12,3\times\left(3,5+24,5\right)\times\left(58\times11-58-58\right)\)

=12,3x28x58x9

=344,4x522

=179776,8

8,0513;     0,6719;     0,035

0,3625

0,02025

0,0056

Ta có: \(\left(x-2\right)^2+1=3,5:0,07\)

=>\(\left(x-2\right)^2+1=50\)

=>\(\left(x-2\right)^2=50-1=49\)

=>\(\left[\begin{array}{l}x-2=7\\ x-2=-7\end{array}\right.\Rightarrow\left[\begin{array}{l}x=7+2=9\\ x=-7+2=-5\end{array}\right.\)

Tìm GTLN đúng ko bn

a) Ta có \(\left|x-3,5\right|\ge0\)

=> \(5-\left|x-3,5\right|\le5\)

=> \(A\le5\)

Dấu "=" xảy ra khi |x-3,5| = 0

=> x-3,5 = 0

x = 0+3,5

x = 3,5

Vậy A_max = 5 tại x = 3,5

Câu b tương tự nha 

Sửa đề:: 0,01x0,1+0,01x0,7+0,05x0,01+25x0,01

=0,01x(0,1+0,7+0,05+25)

=0,01x25,85

=0,2585

(2,4:0,2+5,6)x18

=(12+5,6)x18

=17,6x18

=316,8

42,5:0,1+36,5:0,01-42,65

=425+3650-42,65

=4075-42,65

=4032,35

\(x\times3,5-x\times2=30\)
\(x\times\left(3,5-2\right)=30\)
\(x\times1,5=30\)
\(x=30:1,5\)
\(x=20\)

\(3,5\times x-2\times x=30\\ \Leftrightarrow x\left(3,5-2\right)-30\\ \Leftrightarrow1,5x=30\\ \Leftrightarrow x=30:1,5\\ \Leftrightarrow x=20\)

Vậy \(x=20\)

Câu đầu thiếu ngoặc bạn ơi.

a, 13,5-x+5,4=4,32

=>-x=4,32-13,5-5,4

=>-x=-14,58

=>x=14,58

b,5,1-13,8+x=1

=>x=1-5,1+13,8

=>x=9,7

c,0,16:(x:3,5)=2,8

=>x:3,5=0,16:2,8

=>x:3,5=2/35

=>x=2/35x3,5

=>x=0,2