Question

If 2 1n x + 1n 5 = 1n 80, then what is the value of x?

Answer 1

Answer: A

Given:

`2\ln x+\ln 5=\ln 80`

*subtract ln 5 from both sides:

`2\ln x=\ln 80-\ln 5`

*Divide both sides by 2

`\ln x=(\ln 80-\ln 5)/(2)`
`\ln x=(\ln ((80)/(5)))/(2)`
`\ln x=(\ln (16))/(2)=(\ln (2^4))/(2)`
`\ln x=(4\ln (2))/(2)`
`\ln x=2\ln (2)`
`\ln x=\ln (2^2)`
`\ln x=\ln (4)`
`x=4`