Make x the subject of the formula. r + √(x) = 9 ​

Question

Make x the subject of the formula.

`r + √(x) = 9`
​

Answer 1

Hi there! Given the equation below.

`\large{r + √(x) = 9}`

First is to subtract both sides by r-term to isolate x-term.

`\large{r + √(x) - r = 9 - r} \\ \large{ √(x) = 9 - r}`

Because the x-term is in square root form. We have to square both sides to get rid of the square root.

`\large{( √(x))^(2) = {(9 - r)}^(2) } \\ \large{x = {(9 - r)}^(2) }`

Alternative Solution

`\large{x = {r}^(2) - 18r + 81}`

Answer

• x = (9-r)²
• x = r²-18r+81

Both answers work. Any questions about this can be asked through comment.