a) 213 - 2 x X = 47
2 x X = 213 - 47
2 x X = 166
X = 166 : 2
X = 83
b) 3 x ( X + 1 ) - 300 = 906
3 x ( X + 1 ) = 906 + 300
3 x ( X + 1 ) = 1206
X + 1 = 1206 : 3
X + 1 = 402
X = 402 - 1
X = 401
c) \(\frac{7}{3}-\frac{2}{3}\times x=\frac{1}{4}\)
\(\frac{2}{3}\times x=\frac{7}{3}-\frac{1}{4}\)
\(\frac{2}{3}\times x=\frac{25}{12}\)
\(x=\frac{25}{12}:\frac{2}{3}\)
\(x=\frac{25}{8}\)
d) \(\frac{2}{5}\times x+\frac{7}{8}=2\)
\(\frac{2}{5}\times x=2-\frac{7}{8}\)
\(\frac{2}{5}\times x=\frac{9}{8}\)
\(x=\frac{9}{8}:\frac{2}{5}\)
\(x=\frac{45}{16}\)
Học tốt #
a) \(213-2\cdot x=47\)\(\Leftrightarrow2\cdot x=166\Leftrightarrow x=83\)
b)\(3x\left(x+1\right)-300=906\Leftrightarrow3x\left(x+1\right)=606\)
\(\Leftrightarrow x\left(x+1\right)=202\Leftrightarrow x^2+x-202=0\)
\(\Leftrightarrow\left(x+\frac{1}{2}\right)^2-202,25=0\)\(\Leftrightarrow\orbr{\begin{cases}x+\frac{1}{2}=\sqrt{202,25}\\x+\frac{1}{2}=-\sqrt{202,25}\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=\sqrt{202,25}-0,5\\x=-\sqrt{202,25}-0,5\end{cases}}\)
a) 213 - 2*x = 47
2*x = 213 - 47
2*x = 126
x = 63
các phần cn lại bn lm tương tự nha!
a) 213-2.x=47 b)3.(x+1)-300=906
2.x=213-47 (x+1)-300=906:3
2.x=166 (x+1)-300=302
x=166:2 (x+1)=302+300
x=83 x+1=602
x=602-1
x=601
c) 7/3-2/3.x=1/4 d)2/5.x+7/8=2
2/3.x=7/3-1/4 2/5.x=2-7/8
2/3.x=25/12 2/5.x=9/8
x=25/12:2/3 x=9/8:2/5
x=25/8 x=35/16
dấu. là dấu nhân nha bạn!
213 - 2 x X = 47
2 x X = 213 - 47
2 x X = 166
X = 166 : 2
X = 83
3 x ( x + 1 ) - 300 = 906
3 x ( x + 1 ) = 906 + 300
3 x ( x + 1 ) = 1206
x + 1 = 1206 : 3
x + 1 = 402
x = 402 - 1
x = 401
