Question

`- 10 * 18 {r}^( - 8) = - 2`
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Answer 1

1.107 = r

Explanation:

To solve this for r, do the following:

Add 10 to both sides, to isolate the r term on the left: 18r^(-8) = 8

Divide both sides by 18, to isolate r^(-8): r^(-8) = 8/18

Invert both sides: r^8 = 9/4

Take the natural log or both sides:

8 ln r = ln 9 - ln 4, or

8 ln r = 0.8109, so that ln r = 0.1014

to find r, raise e to the power ln r on the left and e to the power 0.1014 on the right:

ln r 0.1014

e = e = 1.107 = r