A * 1,25 + 2,5 = 1,25 * 9
A * 1,25 + 2,5 = 11,25
A * 1.25 = 11,25 - 2,5
A * 1,25 = 8,75
A = 8,75 : 1.25
A = 7
\(A\times1,25+2,5=1,25\times9\)
\(\Rightarrow A\times1,25+2,5=11,25\)
\(\Rightarrow A\times1,25=11,25-2,5\)
\(\Rightarrow A\times1,25=8,75\)
\(\Rightarrow A=8,75\div1,25\)
\(\Rightarrow A=7\)
Vậy A=7
a x 1,25 + 2,5 = 1,25 x 9
a x 1,25 + 2,5 = 11,25
a x 1,25 = 11,25 - 2,5
a x 1,25 = 8,75
a = 8,75 : 1,25
a = 7
Chúc bạn học tốt !
A*1,25+2,5=1,25*9
A*3,75=11,25
A=11,25:3,75
A=3