Cracking The SAT Premium

2 x =   50

Divide each side of the equation by 2. Thus, x equals 25.

The skills for algebraic manipulation work just as well for more complex equations. The following
question is another example of the way the SAT may ask you to manipulate equations. Don’t panic when
you see a question like this; just use the skills you already have and work carefully so you don’t make an
avoidable mistake in your algebra.

A   Little  Terminology

Here    are some    words   that    you will    need    to  know    to  understand  the explanations    in  this    chapter.

These   words   may even    show    up  in  the text    of  a   question,   so  make    sure    you are familiar    with    them.

Term:   An  equation    is  like    a   sentence,   and a   term    is  the equivalent  of  a   word.   It  can be  just    a   number,

just    a   variable,   or  a   number  multiplied  by  a   variable.   For example,    18, –2x,    and 5y  are the terms   in

the equation    18  –   2x  =   5y.

Expression: If  an  equation    is  like    a   sentence,   then    an  expression  is  like    a   phrase  or  a   clause. An

expression  is  a   combination of  terms   and mathematical    operations  with    no  equal   or  inequality  sign.

For example,    9   ×   2   +   3x  is  an  expression.

Polynomial:  A   polynomial  is  any     expression  containing  two     or  more    terms.  Binomials   and

trinomials  are both    examples    of  polynomials.

10.Suppose  the evaporation rate    of  water   in  a   lake    is  given   by  the equation    E   =   

,   where   E   is  the evaporation rate    in  gallons/day,    Ta  is  the air temperature,    Td  is  the dew

point   temperature,    V   is  the volume  of  water   in  the lake,   Tw  is  the water   temperature,    and h

is  the number  of  hours   the water   is  exposed to  sunlight.   Which   of  the following   expresses

Tw  in  terms   of  Ta, Td,V,   E,  and h?

A) Tw   =   

B) Tw   =