Toán Lớp 7: Tìm x, biết:
a) ( 2x +1 )^3 = -8 b) ( x – 3 )^2 = 25
c) ( 3^x/2^x ) = ( 5/2 – 1 )^3 d) 2^x + 2^x+2 = 40
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Toán Lớp 7: Tìm x, biết:
a) ( 2x +1 )^3 = -8 b) ( x – 3 )^2 = 25
c) ( 3^x/2^x ) = ( 5/2 – 1 )^3 d) 2^x + 2^x+2 = 40
Comments ( 1 )
#Kaito kid
a,$(2x+1)^{3}$=$-2^{3}$
2x+1=-2 ⇒x=$\frac{-3}{2}$
b,$(x-3)^{2}$=25
$(x-3)^{2}$=$5^{2}$
x-3=5 ⇒x=8