1^st Hour Topics 1 Name: _____________________________________

Don’t Forget!

Commute: a + b = b + a or a*b = b*a

Associate: (a + b) + c = a + (b + c) or (a*b)*c = a*(b*c)

Distribute: a*(b + c) = a*b + a*c (read backwards to collect) J

Identities:

When an expression can be written different ways and still mean the same thing, the two are said to be identical to each other or “identities.”

1) -x = -1*x

2) x = 1*x

3) a – b = a +–b

4) a/b = a * (1/b)

5) (a/b) * (c/d) = (a*c) / (b*d)

Identity 1 Practice

Rewrite the following expressions using the first identity.

a) -5 =

b) -(-6) =

c) -(x + 3a) =

d) -1*4 =

e) -x + -1*5 =

Identity 2 Practice

Rewrite the following expressions using the second identity

a) 7 =

b) m =

c) -10 =

d) 1*(2x+1) =

d) 1* (-y) =

Identity 3 Practice

Rewrite the following expressions using the third identity

a) x – 8

b) 6 – (x + 3)

c) 5 - -6 = 5 + -(-6)

d) x + –y

Identity 4 Practice

Rewrite the following expressions using the fourth identity

a) y / 5

b) (x + 3) / (y + 1)

c) 5 * (1 / x)

d) (4x) * (1 / (m – 2)

Identity 5 Practice

Rewrite the following expressions using the fifth identity

a) (5 / x) * (y / 2)

b) (m / 4) * (3 / (x + 2))

c) (-2 / x ) * (y / 8)

d) (4 * x) / ((y + 2) * 7)