Toán Lớp 6: a)59+(-18)+141-82
B)87.39+16.39-39.3
c)8²⁰²²:8²⁰²¹-20:2²+2020⁰
Bài2 a)x-29=-12
B)3.(x+1)+39=27
C)(x-3)²=-2.3²+54
Leave a reply
Register Now
Login
Lost Password
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Toán Lớp 6: a)59+(-18)+141-82
B)87.39+16.39-39.3
c)8²⁰²²:8²⁰²¹-20:2²+2020⁰
Bài2 a)x-29=-12
B)3.(x+1)+39=27
C)(x-3)²=-2.3²+54
Comments ( 1 )
a)59 + \left( { – 18} \right) + 141 – 82\\
= 59 + 141 – \left( {18 + 82} \right)\\
= 200 – 100\\
= 100\\
b)87.39 + 16.39 – 39.3\\
= 39.\left( {87 + 16 – 3} \right)\\
= 39.100\\
= 3900\\
c){8^{2022}}:{8^{2021}} – 20:{2^2} + {2020^0}\\
= {8^1} – 20:4 + 1\\
= 8 – 5 + 1\\
= 4\\
B2)\\
a)x – 29 = – 12\\
\Leftrightarrow x = – 12 + 29\\
\Leftrightarrow x = 17\\
Vậy\,x = 17\\
b)3.\left( {x + 1} \right) + 39 = 27\\
\Leftrightarrow 3.\left( {x + 1} \right) = 27 – 39\\
\Leftrightarrow 3.\left( {x + 1} \right) = – 12\\
\Leftrightarrow x + 1 = – 4\\
\Leftrightarrow x = – 5\\
Vậy\,x = – 5\\
c){\left( {x – 3} \right)^2} = – {2.3^2} + 54\\
\Leftrightarrow {\left( {x – 3} \right)^2} = – 2.9 + 54\\
\Leftrightarrow {\left( {x – 3} \right)^2} = 36\\
\Leftrightarrow \left[ \begin{array}{l}
x – 3 = 6\\
x – 3 = – 6
\end{array} \right.\\
\Leftrightarrow \left[ \begin{array}{l}
x = 9\\
x = – 3
\end{array} \right.\\
Vậy\,x = 9;x = – 3
\end{array}$