Domain restriction — Algebra II, what it means and where it is taught
A square root needs its inside to be ≥ 0, which limits the inputs allowed.
Taught in Algebra II.
Where it is taught
What it rests on
Work through these first if this one does not settle.
- Square root — For k ≥ 0, √k is the nonnegative number whose square is k.
Practise this idea
5 questions in the course bank use Domain restriction, in Rational Expressions & Equations.
Problem 1
Simplify 6x23x.
Worked answer
2x
6 ÷ 3 = 2
x2 ÷ x = x
Keep the original domain restriction: x≠0.
Problem 2
Simplify x2-9x+3.
Worked answer
x-3
(x-3)(x+3)x+3
Cancel the shared factor
Keep the original domain restriction: x≠-3.
Problem 3
Simplify 2x · x5.
Worked answer
2/5
C
a
n
c
e
l
b
e
f
o
r
e
m
u
l
t
i
p
l
y
i
n
g
.
Keep the original domain restriction: x≠0.
Problem 4
Simplify x2-4x2+4x+4.
Worked answer
(x-2)/(x+2)
(x-2)(x+2)(x+2)2
Cancel one (x+2)
Keep the original domain restriction: x≠-2.
Problem 5
Simplify x3 ÷ x6.
Worked answer
2
x3 · 6x
=63=2
Keep the original domain restriction: x≠0.