Posted by **Frank** on Sunday, May 2, 2010 at 11:42pm.

1.) Find the domain and range for:

f(x)= 4x-20/ the square root of 36-x^2

2.) Solve the equation:

log6 (x-11) + log6 (x-6) = 2

3.) Solve the inequality:

x^2 - 2x - 3 is greater than 0

- Math SAT Sheet -
**Reiny**, Monday, May 3, 2010 at 12:22am
1. remember that the denominator √(36 - x^2) cannot be zero or negative,

so shouldn't -6 < x < +6 ??

2. log6 [(x-11)(x-6)] = 2

(x-11)(x-6) = 6^2

x^2 - 17x + 66 = 36

x^2 - 17x + 30 = 0

(x-15)(x-2) = 0

x = 15 or x = 2

A lot of students would stop here and think they have the right answer, but remember that we can only take logs of positive numbers, so looking at our original we can see clearly that x > 11

so x = 15 is the only answer.

- Math SAT Sheet -
**Reiny**, Monday, May 3, 2010 at 12:26am
3. x^2 - 2x - 3 > 0

(x-3)(x+1) > 0

"critical" values are x = 3 and x = -1

try a number < -1, say x = -5

statement: (-8)(-4) > 0 ? YES

try a number between -1 and 3, say x = 0

statement: (-3)(1) > 0 False!

try a number > 3, say x = 5

statement: (2)(6)>0 YES

so x < -1 OR x > 3, x any real number.

## Answer This Question

## Related Questions

- precalulus - Ok feeling kinda dumb because this isn't coming out right. I know ...
- Math - The problem I have to solve is log with base 2 ^6 multiply by log base 6...
- Algebra 2 - Can someone please explain to me how to solve logarithmic equations...
- Math - Solve the equation. (the 6s are supposed to be sub-scripted, but I can't ...
- Math - Which of the following is equal to log6(t + 1) − log6(t^2 − 1...
- SAT math - 1. If square root of 3x-11 +10 = 17, find the value of 10 x . I don't...
- MAth - how do i find the domain and range of equations? example: f(x)=ab.solute ...
- Math - log6(x+7)−log6x=2 Solve for x
- Pre Algebra - Please help me with some problems. Thank you! Solve the equation ...
- Logs - log6(x+7)−log6x=2 Solve for x

More Related Questions