SAT Mc Graw Hill 2011

CHAPTER 8 / ESSENTIAL ALGEBRA I SKILLS 321

7.D Plugging in x=1 gives you 0 + 1 + 2 =3, and
(D) is the only choice that yields 3. Or:

x

x

x

x

x

x

xx

x

2 1 22

1

11

2

21

3

11

−

+

+

()+ −

+

+

()+ −

+

=

()+ ()−

++

+

()++()+−

+

+

()++()+−

+

=−

1

11 11

2

21 21

3

1

xx

x

xx

x

()(x +()xx++()^13 = x

8.B

Substitute

9.E

Square both sides:

Add 2: n

n

(^22) x 2

1

+=+ 2

n

n

n

n

− x

⎛

⎝⎜

⎞

⎠⎟

=−+ =()

1

2

1

2

2

2

2

n

n

−=x

1

yp

p

p

p

p

p

p

=

()+

()−

=

()+

()−

=

+

−

3

36

36

32

32

2

2

:

y

y

yy

yy

y

y

2

2

36

6

66

66

6

6

−

()−

=

()− ()+

()− ()−

=

()+

()−