Question

Tìm x :

a, 60 - 3 ( x -2 ) = 51

b, ( 105 - x ) : 2 mũ 5  = 3 mũ 0 + 1

c, x + 5 = 20 - ( 12 - 7 )

Answer 1

a) \(60-3.\left(x-2\right)=51\)

\(\Rightarrow3.\left(x-2\right)=60-51=9\)

\(\Rightarrow x-2=9:3=3\)

\(\Rightarrow x=3+2=5\)

b) \(\left(105-x\right):2^5=3^{0+1}=3^1=3\)

\(\Rightarrow\left(105-x\right):32=3\)

\(\Rightarrow105-x=3.32=96\)

\(\Rightarrow x=105-96=9\)

c) \(x+5=20-\left(12-7\right)\)

\(\Rightarrow x+5=20-5\)

\(\Rightarrow x+5=15\)

\(\Rightarrow x=15-5=10\)