Question

Giải hộ mik bài này nha

a (2x + 1)² =81

b (3 - x)⁴ = 1

c (x + 4)³ = 125

Answer 1

Đề bài ??? 

Answer 2

a) \(\left(2x+1\right)^2=81\)

\(\Rightarrow\left(2x+1\right)^2=9^2\)

\(\Rightarrow2x+1=9\)

\(\Rightarrow2x=9-1=8\)

\(\Rightarrow x=8:2=4\)

\(\Rightarrow x=4\)

b)\(\left(3-x\right)^4=1\)

\(\Rightarrow\left(3-x\right)^4=1^4\)

\(\Rightarrow3-x=1\)

\(\Rightarrow x=3-1=2\)

\(\Rightarrow x=2\)

c) \(\left(x+4\right)^3=125\)

\(\Rightarrow\left(x+4\right)^3=5^3\)

\(\Rightarrow x+4=5\)

\(\Rightarrow x=5-4=1\)

\(\Rightarrow x=1\)

k mk nha. CHÚC BẠN HỌC TỐT. ^_^

Answer 3

a) \(\left(2x+1\right)^2=81\)

\(\left(2x+1\right)^2=9^2\)

\(\Rightarrow2x+1=9\)

\(\Rightarrow2x=9-1\)

\(\Rightarrow2x=8\)

\(\Rightarrow x=8:2\)

\(\Rightarrow x=4\)

b) \(\left(3-x\right)^4=1\)

Answer 4

b) \(\left(3-x\right)^4=1\)

\(\left(3-x\right)^4=1^4\)

\(\Rightarrow3-x=1\)

\(\Rightarrow x=3-1\)

\(\Rightarrow x=2\)

c) \(\left(x+4\right)^3=125\)

\(\left(x+4\right)^3=5^3\)

\(\Rightarrow x+4=5\)

\(\Rightarrow x=5-4\)

\(\Rightarrow x=1\)

Answer 5

\(a,\left(2x+1\right)^2=81\)

\(\Rightarrow\left(2x+1\right)^2=9^2\)

\(\Rightarrow2x+1=9\)

\(\Rightarrow2x=8\)

\(\Rightarrow x=4\)

\(b,\left(3-x\right)^4=1\)

\(\Rightarrow\left(3-x\right)^4=1^4\)

\(\Rightarrow3-x=1\)

\(x=2\)

\(c,\left(x+4\right)^3=125\)

\(\Rightarrow\left(x+4\right)^3=5^3\)

\(\Rightarrow x+4=5\)

\(\Rightarrow x=9\)