Find the interval on whitch the expression is ...


Find the interval on whitch the expression is defined:?x?2-7x-8 That’s the square root of the trinomial (x squared - 7x - 8)


I am thoroughly confused- they gave us the answers, but we need to show how we got them, so I need help.


The answer is (-?, -1], [8,?) That’s (negative infinity, -1], [8, infinity)


Liked this question? Tell your friends about it

Best Answer

The expression x^2-7x-8 can be factored as (x+1)(x-8).  That will be a positive quantity if x is greater than 8 (both terms positive), or less than -1 (both terms negative).  The square root of a positive quantity is a real number.  The square root of a negative quantity is not a real number, so it is not defined between -1 and +8.

All Answers

Order by
Oldest to Newest
Newest to Oldest

Algebraic expressions can be multiplied together. An algebraic expression may consist of a number  ( coefficient ), a letter ( variable, and/or an exponent.

When you multiply variables with exponents, you can add the exponents if the variables are the same.

Some problems require factoring algebraic expression. to factor means to

find and separate numbers that have been multiplied.   In an expression of four or more terms, you can use the method of factoring by grouping to factor the expression. 


In simple words: They are asking you what is the range that this function (X^2-7X-8) is possitive or zero.    Since X^2-7X-8 equals to (X+1)*(X-8)  this function is possitive or zero if X is > 8 (until infinity)   0r  X < -1  (untill minus infinity). 

Love is the battery of life....

Related Questions

Other people asked questions on similar topics, check out the answers they received:

Asked: Precalculus EXAM STUDY HELP PLEASE ASAP!!!!!

Hey. I have a Pre-Calculus exam tomorrow, and I was given a series of questions to study for, as well as the answers to them. The only problem is, there are a few problems I can't figure out how to ...

Asked: Which category can you NOT win a Nobel Prize in ...

Which category can you NOT win a Nobel Prize in Mathematics or Economics?

Asked: A2 Mathematics help please

The variables x and t satisfy the differential equation t dx/dt = (k-x^3)/2x^2 for t > 0, where k is a constant. When t = 1, x = 1 and when t = 4, x = 2. (i) Solve the differential equation, finding ...

Ask a Question... We'll forward it to people who know

More Questions

Graph of intervals

This graph is a straight numbered line with -4 at on the left and 10 on the right with closed circles because the numbers are included.

his interval fifa 15 coins

fifa1314 has updated cheap fut fifa15 coins you can buy now!!! click: With 5% Coupon Code: FIFA1314COINSJYY07 (5% more coins)

How do I view my own expressions?

A mirror or other reflective device would show you.

Where can I find the

Hi Jack: For assistance, please refer to the help article below. Customize your AOL Sounds