Toán Lớp 6: a) 49 : (2mũ x – 9) = 4 ² – 3 ²
b) 3mũ x+1 . 5 – 10 : 2 + 5 = 15
3 mũ x +1( 1 ở phần mũ
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Toán Lớp 6: a) 49 : (2mũ x – 9) = 4 ² – 3 ²
b) 3mũ x+1 . 5 – 10 : 2 + 5 = 15
3 mũ x +1( 1 ở phần mũ
Comments ( 2 )
49:(2^x-9)=4^2-3^2
=>49:(2^x-9)=16-9
=>49:(2^x-9)=7
=>2^x-9=49:7
=>2^x-9=7
=>2^x=7+9
=>2^x=16
=>2^x=2^4
=>x=4
Vậy x=4
b)
3^(x+1) . 5-10:2+5=15
=>3^x . 3 . 5-5+5=15
=>3^x . 15=15
=>3^x =15:15
=>3^x=1
=>3^x=3^0
=>x=0
Vậy x=0