help on math question

Test Preparation SAT Preparation
1

<p>hey, this is from bb on pg. 684.</p>

<p>Let (x) be definded as (x) = x^2 - x for all values of x. If (a) = (a-2), what is the value of a?</p>

<p>Apparently the answer is 3/2. I have no idea why its that answer, so can someone here please help me?</p>

2

<p>If (x) = x^2 - x, then what is (a)? What is (a-2)?</p>

3

<p>f(a)=a^2-a
f(a-2)=(a^2-4a+4)-(a-2) or a^2-5a+6
set them equal to each other and solve</p>

<p>a^2 cancels out, leaving -a=-5a+6
4a=6
a=3/2</p>