12,5 x 7 + 12,5 - 12,5 x 6 + 12,5 x 8

= 12,5 x (7 + 1 - 6 + 8)

= 12,5 x 10 = 125.

Cảm ơn nhìu

a: \(\Leftrightarrow x\cdot12.3=123\)

=>x=10

b: \(\dfrac{3x-0.8}{x}+14.5=15\)

\(\Leftrightarrow\dfrac{3x-0.8}{x}=0.5\)

\(\Leftrightarrow3x-0.8=0.5x\)

=>2,5x=0,8

hay x=8/25

c: \(\Leftrightarrow12.5\cdot x=5.58-4.85=0.73\)

hay x=73/1250

25% - 2x = 12,5 + 3/4 \(\Leftrightarrow\dfrac{1}{4}-2x=\dfrac{53}{4}\) \(\Leftrightarrow2x=-13\Leftrightarrow x=-\dfrac{13}{2}\)

X=-13/2 

\(a,x+3,79=15,12\)\(\Rightarrow x=15,12-3,79\)\(\Rightarrow x=11,33\)

\(b,12,1-x=5,49\)\(\Rightarrow x=12,1-5,49\Rightarrow x=6,61\)

\(c,60,45:x=1,5\)\(\Rightarrow x=60,45:1,5\Rightarrow x=40,3\)

\(d,3,5.x-1,5.x=12,5\)

\(\Rightarrow x\left(3,5-1,5\right)=12,5\)

\(\Rightarrow x.2=12,25\Rightarrow x=12,25:2=6,125\)

\(d,12,5.x-2,5.x-50=2,5.10\)

\(\Rightarrow12,5.x-2,5.x-50=25\)

\(\Rightarrow x\left(12,5-2,5\right)=25+50\)

\(\Rightarrow x.10=75\)

\(\Rightarrow x=75:10=7,5\)

a) x=11,33                  b) x=6,61                  c)40,3

     Mình chỉ biết làm tới đó thôi. xin lỗi nha

a, 12,5 x 4 - x = 4,3+2,6

50 - x = 6,9

x=50-6,9

x=43,1

câu b sao lại bằng 0,9 z

Có cần ghi lời giải ko bạn

a) \(12,5.4-x=4,3+2,6.\)

\(\Rightarrow12,5.4-x=6,9\)

\(\Rightarrow50-x=6,9\)

\(\Rightarrow x=50-6,9=43,1\)

b) \(\left(x+0,9\right).\left(1-0,4\right)=2412\)

\(\Rightarrow\left(x+0,9\right).0,6=2412\)

\(\Rightarrow x+0,9=2412:0,6=4020\)

\(\Rightarrow x=4020-0,9=4019,1\)

Ủng hộ mik nha!