Question

[Khánh Đặng]

Tìm X

Xx2+15=1,5x(x+20)

Answer 1

[I don't need you]

\(x\times2+15=1,5\times\left(x+20\right)\)

\(x\times2+15=1,5\times x+30\)

\(\Rightarrow x\times2-1,5\times x=30-15\)

\(x\times\left(2-1,5\right)=15\)

\(x\times0,5=15\)

\(x=15:0,5\)

\(x=30\)

Answer 2

[Nguyễn Thanh Hiền]

\(x\times2+15=1,5\times\left(x+20\right)\)

\(\Rightarrow x\times2+15=1,5\times x+\left(1,5\times20\right)\)

\(\Rightarrow x\times2+15=1,5\times x+30\)

\(\Rightarrow1,5\times x-x\times2=15-30\)

\(\Rightarrow\left(1,5-2\right)\times x=-15\)

\(\Rightarrow-0,5\times x=-15\)

\(\Rightarrow x=-15:-0,5\)

\(\Rightarrow x=30\)

Vậy x  = 30

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