Question

Tìm x biết

219-7 ( x+1 ) = 10²

( 3x - 2⁴ ) . 7³ = 2.7⁴

Answer 1

Lời giải:

$10+2x=4^5:4^3=4^2=16$

$2x=16-10=6$

$x=6:2=3$

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$2x-6^2:18=3.2^2$
$2x-2=12$

$2x=14$

$x=14:2=7$

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$70-5(x-3)=3.2^5=96$

$5(x-3)=70-3.2^5=-26$

$x-3=\frac{-26}{5}$

$x=3+\frac{-26}{5}=\frac{-11}{5}$

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$19-7(x+1)=10^2=100$

$7(x+1)=19-100=-81$

$x+1=\frac{-81}{7}$

$x=\frac{-81}{7}-1=\frac{-88}{7}$

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$(3x-2^4).7^3=2.7^4$

$3x-16=2.7^4:7^3=2.7=14$

$3x=14+16=30$

$x=30:3=10$