linhpham linh
\(\left(x+\frac{3}{4}\right)^2=\frac{49}{16}\)
\(\Rightarrow\left(x+\frac{3}{4}\right)^2=\frac{7^2}{4^2}\)
\(\Rightarrow\left(x+\frac{3}{4}\right)^2=\left(\frac{7}{4}\right)^2\)
\(\Rightarrow x+\frac{3}{4}=\frac{7}{4}\)
\(\Rightarrow x=\frac{7}{4}-\frac{3}{4}\)
\(\Rightarrow x=1\)
a) \(\left(x+\frac{3}{4}\right)^2=\frac{49}{16}\)
=> x + \(\frac{3}{4}=\frac{7}{4}\)
=> x = \(\frac{7}{4}-\frac{3}{4}=\frac{4}{4}=1\)
c) (3x - 1)2 = 81
=> 3x - 1 = 9
=> 3x = 10
=> x = \(\frac{10}{3}\)
a) \(\left(x+\frac{3}{4}\right)^2=\left(\frac{7}{4}\right)^2\)
\(\Rightarrow x+\frac{3}{4}=\frac{7}{4}\)
\(\Rightarrow x=\frac{7}{4}-\frac{3}{4}\)
\(\Rightarrow x=1\)
b) \(9^{3x+1}=9^{x+13}\)
\(\Rightarrow3x+1=x+13\)
\(\Rightarrow3x-x=13-1\)
\(\Rightarrow2x=12\)
\(\Rightarrow x=12:2\)
\(\Rightarrow x=6\)
c) \(\left(3x-1\right)^2=81\)
\(\Rightarrow\left(3x-1\right)^2=9^2\)
\(\Rightarrow3x-1=9\)
\(\Rightarrow3x=9+1\)
\(\Rightarrow3x=10\)
\(\Rightarrow x=10:3\)
\(\Rightarrow x=\frac{10}{3}\)
a) suy ra (x+3/4)^2=\(\left(\frac{7}{4}\right)^2hoặc\left(\frac{-7}{4}\right)^2\)
suy ra x+3/4 = 7/4 hoặc -7/4
x= 1 hoặc x=-10/4
b) suy ra 3x+1 = x+13 , suy ra 3x-x=13-1
suy ra 2x =12, suy ra x=6
suy ra (3x-1)^2=9^2 hoặc (3x-1)^2=-9^2
suy ra 3x-1=9 hoặc 3x-1=-9
suy ra3x=10 hoặc 3x=-8
suy ra x=10/3 hoặc x=-8/3
bài này trình bày đẹp thì cậu dùng kí hiệu [ ] nhé
câu a (74)2 thực ra là (7/4)^2, (-74)2 thực ra là (-7/4)^2 nha bạn, sorry