TheXSquaredFactor

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Questions 3
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 #1
avatar+2446 
+2

\((x-\sqrt{48})^2\leq\frac{49}{3}\) 

 

I am sorry if I have interpreted your inequality incorrectly. I am fairly certain that the equation above is what you were attempting to convey.

 

\((x-\sqrt{48})^2\leq\frac{49}{3}\) Undo the square by square rooting both sides of the inequality.
\(x-\sqrt{48}\leq|\sqrt{\frac{49}{3}}|\) Remember the square root rule that states that \(\sqrt{\frac{a}{b}}=\frac{\sqrt{a}}{\sqrt{b}}\). I like to think of it as "distributing" the square root into both the numerator and denominator. Also, the square root function always results in a negative and positive answer. That's why the absolute value sign is there.
\(x-\sqrt{48}\leq|\frac{\sqrt{49}}{\sqrt{3}}|\) Simplify the fraction on the right side of the equation.
\(x-\sqrt{48}\leq|\frac{7}{\sqrt{3}}|\) Let's rationalize the right hand side of the equation by multiplying the numerator and denominator by 
\(\frac{7}{\sqrt{3}}*\frac{\sqrt{3}}{\sqrt{3}}=\frac{7\sqrt{3}}{3}\) Reinsert this back into the inequality.
\(x-\sqrt{48}\leq|\frac{7\sqrt{3}}{3}|\) The absolute value results in 2 answers: the positive and negative. Let's split that up.
\(x-\sqrt{48}\leq\pm\frac{7\sqrt{3}}{3}\)  

 

Now, we must evaluate each inequality separately. The one for the plus and the one for the minus. To make it easier, I'll solve both one at a time! I'll do the positive version first:

 

\(x-\sqrt{48}\leq\frac{7\sqrt{3}}{3}\) Add \(\sqrt{48}\) to both sides.
\(x\leq\frac{7\sqrt{3}}{3}+\sqrt{48}\) First, I'll make\(\sqrt{48}\) into simplest radical form.
\(\sqrt{48}=\sqrt{16*3}=\sqrt{16}\sqrt{3}=4\sqrt{3}\) Ok, because this radical is in simplest radical form, reinsert it back into the equation. 
\(x\leq\frac{7\sqrt{3}}{3}+\frac{4\sqrt{3}}{1}\) Put \(\frac{4\sqrt{3}}{1}\) into a common denominator so that it is possible to add them together.
\(\frac{4\sqrt{3}}{1}*\frac{3}{3}=\frac{12\sqrt{3}}{3}\) Now that this fraction has a common denominator, let's add them together.
\(x\leq\frac{7\sqrt{3}}{3}+\frac{12\sqrt{3}}{3}\) Add the fractions together. 
\(x\leq\frac{19\sqrt{3}}{3}\) Time to solve the second part of the equation.
   

 

Now, we have to solve for the other scenario, \(x-\sqrt{48}\geq-\frac{7\sqrt{3}}{3}\). Now, this is a tad difficult to explain, but the absolute value function does funny things to an inequality. The rule is that \(|f(x)|\leq a\Rightarrow f(x)\leq a\hspace{1mm}\text{and}\hspace{1mm}f(x)\geq -a\)

 

\(x-\sqrt{48}\geq-\frac{7\sqrt{3}}{3}\) Solve and isolate x by adding \(\sqrt{48}\) to both sides.
\(x\geq-\frac{7\sqrt{3}}{3}+\sqrt{48}\) Put \(\sqrt{48}\) into simplest radical form and put in common denomator. Because I have already done this in the previous equation, I'll just skip.
\(x\geq-\frac{7\sqrt{3}}{3}+\frac{12\sqrt{3}}{3}\) Add the fractions together now.
\(x\geq\frac{5\sqrt{3}}{3}\)  
   

 

Now, put the solutions together.

 

\(\frac{5\sqrt{3}}{3}\leq x\leq \frac{19\sqrt{3}}{3}\)

.
 #1
avatar+2446 
+2

Evaluating these algebraid expressions just requires you to substitute in the values given for the variable. Let's do the first one together:
 

1. \(N^2-25\)

 

a) When n=-10

 

\(N^2-25\) Replace N, the variable, with -10 and evaluate from there.
\((-10)^2-25\) Do \((-10)^2=-10*-10=100\) first so to adhere to the order of operations. 
\(100-25\)  
\(75\)  
   

 

The process repeats for the other values for N

 

b) n=-5

 

\(N^2-25\)  
\((-5)^2-25\)  
\(25-25\)  
\(0\)  
   

 

c) n=1/2

 

\(N^2-25\)  
\((\frac{1}{2})^2-25\) Remember that squaring a fraction follows the rule that \((\frac{a}{b})^2=\frac{a^2}{b^2}\)
\(\frac{1^2}{2^2}-25\) Simplify the fraction.
\(\frac{1}{4}-25\) Change 25 to an improper fraction so that you can subtract it from 1/4.
\(\frac{25}{1}*\frac{4}{4}=\frac{100}{4}\) Now that we have changed 25 to a fraction with a common denominator, reinsert it back into the equation.
\(\frac{1}{4}-\frac{100}{4}\) Subtract the fractions.
\(-\frac{99}{4}=-24\frac{3}{4}\) The fraction is already in simplest form. I've provided both versions of the answer.
   

 

d) n=9

 

\(N^2-25\)  
\(9^2-25\)  
\(81-25\)  
\(56\)  
   

 

I'll do half of the next one and the rest are up to you to complete:

 

2. \(\frac{-7d+14}{2}\)

 

a) d=2

 

\(\frac{-7d+14}{2}\) Substitute the given value for d, 2.
\(\frac{-7*2+14}{2}\) Do -7*2 first.
\(\frac{-14+14}{2}\) Simplify the numerator by calculating -14+14.
\(\frac{0}{2}=0\)  
   
   

 

b) d=-2

 

\(\frac{-7d+14}{2}\)  
\(\frac{-7*-2+14}{2}\) A negative times a negative always results in a positive.
\(\frac{14+14}{2}\)  
\(\frac{28}{2}\) Divide 28 by 2.
\(14\)