How do you find the domain of f(x) = sqrt(7x + 2)?

Oct 7, 2016

Domain: $\left\{x | x \ge - \frac{2}{7}\right\}$ or Domain:$\left[- \frac{2}{7} , \infty\right)$

Explanation:

We know that the we cannot find a real solution to the sqrt of a negative number. This lets me know that $7 x + 2 \ge 0$.

Solve:

$7 x + 2 \ge 0$

$7 x \ge - 2$ (Subtract 2 from both sides.)

$x \ge - \frac{2}{7}$ (Divide both sides by 7.)

This tells us that we can only use x's$\ge - \frac{2}{7}$ in our domain.

Domain: $\left\{x | x \ge - \frac{2}{7}\right\}$ or Domain:$\left[- \frac{2}{7} , \infty\right)$