are these correct?

[chrystal21]

1. Solve for c: a=square root of 2/bc
a. c=2/a^2b
b. c=2a^2/b
c. c=2b/a^2
d. c=2a^2b
*choice A

2. Solve for x: square root of (5x-6)=x-4
a. 2
b. 4
c. 11
d. 3
e. none of these
*choice a

3. multiply and simplify: cubed root of (9ab^2) cubed root of (9a^4 b^5)
a. 9a^2b^3 cubed root of (a^2b)
b. 3a b^2 cubed root of (3a^2b)
c. 3a b cubed root of (3a b^2)
d. 9a b cubed root of (9a^2 b^2)
*choice B

 

[soroban]

Hello, chrystal21!

1. Solve for $\displaystyle c:\; a\:=\:\sqrt{\frac{2}{bc}}$

$\displaystyle a)\:c\,=\,\frac{2}{a^2b}\;\;\;b)\;c\,=\,\frac{2a^2}{b}\;\;\;c)\;c\,=\,\frac{2b}{a^2}\;\;\;d)\;c\,=\,2a^2b$

*choice A . . . Right!

2. Solve for $\displaystyle x:\;\sqrt{5x\,-\,6}\:=\:x\,-\,4$

$\displaystyle a)\;2\;\;\;b)\; 4\;\;\;c)\; 11\;\;\;d)\; 3\;\;\;e)\;\text{none of these}$

*choice a . . . no

For $\displaystyle x\,=\,2$, the left side is: $\displaystyle \,\sqrt{5\cdot2\,-\,6}\:=\:\sqrt{10\,-\,6}\:=\:\sqrt{4}\:=\:$+2

$\displaystyle \;\;$But the right side is: $\displaystyle \,2\,-\,4\:=\:$-2

The correct answer is: $\displaystyle \,x\,=\,11$ . . . answer (c)

3. Multiply and simplify: $\displaystyle \,\sqrt[3]{9ab^2}\,\cdot\,\sqrt[3]{9a^4 b^5}$

$\displaystyle a)\;9a^2b^3\cdot\sqrt[3]{a^2b}\;\;\;b)\;3a b^2\cdot\sqrt[3]{3a^2b}\;\;\;c)\;3a b\cdot\sqrt[3]{3a b^2}\;\;\;d)\;9ab\cdot\sqrt[3]{9a^2b^2}$

*choice B . . . Correct!