A few days ago
Samich

How do you solve for x?

in logx+log(x-3)=1

and in

(x+3)(x-3)>0

and in

abs(x-3)<7

Top 3 Answers
A few days ago
Annie

Favorite Answer

Let’s take this one problem at a time

1)logx+log(x-3)=1

*Remember since no base is given you are therefore using base 10

For this we use the formula log m + log n = log (m*n)

Here we have m = x and n = (x – 3)

logx+log(x-3)=1 Write original equation

log [ x * ( x – 3)] = 1

10 log [ x * ( x – 3)] = 10 1 Exponentiate each side using base 10

[ x * ( x – 3)] = 10

x2 – 3x = 10

x2 – 3x – 10 = 0Rewrite in simple form

(x – 5) (x + 2) = 0Factor

*Remember the zero product property: when ab = 0, the a = 0, b= 0, or both = 0

(x-5) = 0(x + 2) = 0 Solve both

x = 5x = -2

Check both answers:

When x = 5

log5+log(5-3)=1

log5+log(2)=1

1 = 1

When x = 2

log2+log(2-3)=1

log2+log(-1)=1

log (-1) is not defined, so not a real solution

2)(x+3)(x-3)>0

Use the zero product property as above, just use > instead of =

(x + 3) > 0, subtract 3 from both sides

x < -3 (x-3) > 0, add 3 to both sides

x > 3

You could also graph this one to see which direction to “shade” if you need to graph it as well.

3)|x – 3| < 7 The trick here is to remember that you need both the positive AND the negative values. The positive value: |x – 3| < 7 x – 3 < 7, add three to both sides x < 10 The negative value: (because you set it “equal” to a negative number) *Don’t forget that when you set this to the negative value you need to reverse the inequality sign* x – 3 > -7, add 3 to both sides

x > -4

Your final answer is: -4 < x < 10 Hope this helped!! If you are still confused I would suggest getting some extra problem sets from your teacher so you don’t fall too far behind before the school year starts off. Good luck!

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4 years ago
?
All answer are incorrect or in part staggering! The is a try no rely if the equation holds. because of the fact the quotient x/x is given, the equation is defined for x=0, because of the fact the reality, that there is a genuine decrease for x goint to 0 of x/x: limit_x->0 x/x=a million. So get rid of the quotient a minimum of for x unequal 0. The equation now is x+x²=x². This equation could be rearranged via unique arithmetic operations. It supplies x=0. stupid or. What does is advise? The equation does not carry for x unequal 0. it somewhat is it. it may returned be simplified a million+x=x or a million=0, it somewhat is inaccurate. For 0 is holds interior the stable form and interior the decrease attention: 0/0+0=a million+0 unequal 0. The equation does not be valid for any actual numbers!
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A few days ago
James L
x=5

x>3 or x<-3 -4

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