You are here:

Algebra/need help

Advertisement

Expert: - 10/22/2007


Question
how do you find the zeros for x-sqrtx-12.

Answer
I assume you mean the zeros of

x - x^1/2 - 12

so we try to solve

x - x^1/2 - 12 = 0

x - 12 = x^1/2

square both sides

(x - 12)^2 = x

x^2 - 24x + 144 = x

x^2 - 25x + 144 = 0

(x-9)(x-16) = 0

this gives x = 9 and x = 16 as possible solutions.

Whenever you solve an equation by squaring both sides , you must check your answers back in the original equation

9 doesn't work but 16 does, so the answer is

x = 16

Algebra

All Answers

Answers by Expert:

Ask Experts

Volunteer

Socrates

Expertise

Any questions on High School Algebra, College Algebra, Abstract Algebra. I can help with word problems, solving equations, trigonometry, inequalities, Gaussian Elimination, Linear Algebra, groups, fields, you name it!

Experience

Ph.D. in Mathematics, specialist in Algebra. I have taught High School students and college students at three state universities.

Organizations
Mathematical Association of America. American Mathematical Society.

Publications
Regular contributions to the problems section of the American Mathematical Monthly journal.

Education/Credentials
B.S., M.S., Ph.D.

©2012 About.com, a part of The New York Times Company. All rights reserved.