Question

1/Tìm x:

a/\(\left(-12\right)^2.x=56+10.13x\)

b/\(80-\left(x^2+5\right)=66\)

c/\(9-25=\left(7-x\right)-\left(25+7\right)\)

d/\(\left(x+5\right)^2=16\)

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Answer 1

a) (-12)².x = 56 + 10.13x

=> 144.x = 56 + 130x

=> 144x - 130x = 56

=> 14x = 56

=>x = 56 : 14

=> x = 4

b) 80 - (x² + 5) = 66

=> x² + 5 = 80 - 66

=> x² + 5 = 14

=> x² = 14 - 5

=> x² = 9

=> x² = 3²

=> \(\orbr{\begin{cases}x=3\\x=-3\end{cases}}\)

Answer 2

c) 9 - 25 = (7 - x) - (25 + 7)

=> -16 = (7 - x) - 32

=> 7 - x = -16 + 32

=> 7 - x = 16

=> x = 7 - 16

=> x = -9

d) \(\left(x+5\right)^2=16\)

=> \(\left(x+5\right)^2=4^2\)

=> \(\orbr{\begin{cases}x+5=4\\x+5=-4\end{cases}}\)

=> \(\orbr{\begin{cases}x=-1\\x=-9\end{cases}}\)

Answer 3

a)\(\left(-12\right)^2.x=56+10.13x\)

\(144x=56+130x\)

\(144x-130x=56\)

\(14x=56\)

\(\Rightarrow x=4\)

Answer 4

b) \(80-\left(x^2+5\right)=66\)

\(x^2+5=80-66\)

\(x^2+5=14\)

\(x^2=9\)

\(x^2=3^2=\left(-3\right)^2\)

Vậy : \(x\in\left\{3;-3\right\}\)

Answer 5

80 - ( x² + 5 ) = 66

( x² + 5 ) = 80 - 66

x² + 5 = 26

x² = 21

x = căn 21