Question

Make x the subject of the formula. title="r + \sqrt{x} = 9" alt="r + \sqrt{x} = 9" align="absmiddle" class="latex-formula">
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Answer 1

Hi there! Given the equation below.

$\large{r + \sqrt{x} = 9}$

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

$\large{r + \sqrt{x} - r = 9 - r} \\ \large{ \sqrt{x} = 9 - r}$

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

$\large{( \sqrt{x})^{2} = {(9 - r)}^{2} } \\ \large{x = {(9 - r)}^{2} }$

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.