1. Solve for $h$: $S=2\pi r h+2\pi r^2$
Solution:
The variable $h$ is in the first term on the right, so isolate the first term by subtracting the second term:
$S-2\pi r^2=2\pi rh$
Now, divide $2\pi r$ on both sides:
Swicthing the sides,
$\dfrac{S-2\pi r^2}{2\pi r}=h$
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2. Solve for $y$: $|y+2|-1=10$
First isolate the absolute value, the first term on the left hand side:
$|y+2|=10\color{red}+1$
$|y+2|=11$
$y+2=11$ or $y+2=-11$
Solving,
$y=11-2$ or $y=-11-2$
$y=9$ or $y=-13$
The solutions are,
$\{9, -13\}$ or $\{-13, 9\}$
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3. Solve for $f$: $|7f-2|=-9$
Solution:
Left hand side is the absolute value, $|7f-2|$ that is equal to a negative number $-9$.
Since an absolute cannot be a negative number, the equation has no solution.
We write the no solution as $\varnothing$.
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4. Solve for $h$: $|h+3|+3\le 7$
Solution:
Isolate the absolute value:
$|h+3|=\le 7-3$
$|h+3|=\le 4$
$-4\le h+3 \le 4$
Subtracting $3$:
$-7 \le h \le 1$
Writing this in interval notation:
$[-7, 1]$
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5. Solve for $y$: $|2y-1|+1\gt -7$
Solution:
First isolate the absolute value:$
$|2y-1|\gt -7-1$
$|2y-1|>0$
$2y-1\gt 0$ or $2y-1\lt 0$
Solving these two equations:
$y\gt \dfrac{1}{2}$ or $y\lt \dfrac{1}{2}
Absolute value is greater than a negative number, means, it is greater than zero.
So, all the real numbers are the solution to the equation. This in interval notation is
$(-\infty, \infty)$
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10. Determine whether the relation defines y as a function of x and give the domain.
$y=\sqrt{6x-4}$
$The given function is a square root function with a linear expression inside the square root. This is a one-to-one function:
To find the domain, set the expression inside the square root $\ge 0$
$6x-4\ge 0$
Now, solve for $x$,
$x\ge\dfrac{4}{6}$
Dividing out the common factor $2$, you get
$x\ge \dfrac{2}{3}$
Writing this inequality in interval notation:
$[\dfrac{2}{3}, \infty)$