Refresh Your Skills (RYS) Guide
RYS # Don’t do this Do this Why
1 (x + 5)2 = x2 + 25 = x2 + 10x + 25 (a + b)2 = a2 + 2ab + b2
exponents do not distribute over addition or subtraction
2 write       x - 3/2 
when you mean 
write (x - 3)/2  or  order of operations
3 (cannot be simplified) same reason as #1: think of it as 
4 (calculator) enter e3x as e^3x  enter e^(3x) e^3x means e3x (order of operations)
5*

 

3x = 12
3x/3 = 12/3
x = 4
do it in your head, just write: 
x = 4
you can move the multiplier 3 to the other side of the equation by making it a divisor
6*

 

x + 1 =    5
     -1     -1
-------------
x       =    4
do it in your head, just write: 
x = 4
you can just move the term 1 to the other side of the equation and change its sign
| x + 7| + 3 = x + 10 (cannot be simplified) usually can’t just discard abs. value signs as if they were meaningless
8 log (a + b) = log a + log b (cannot be simplified) log (ab) = log a + log b
can’t have it both ways!
9* (x + 2)(x + 3) =
x2 + 2x + 3x + 6
just write answer:
x2 + 4x + 6
for a product like this, the OI of FOIL can be combined in your head
10*

 

(x + 3)2 = (x+3)(x+3) = x 2 +6x+9 just write the answer: x2 + 6x + 9

 

use the formula:
(a + b)2 = a2 + 2ab + b2
and do it in your head
11

 


(by cancelling the x's)
fraction cannot be simplified can’t cancel common terms out of numerator and denominator; can cancel factors: (a b)/b = a/1 = a
12 (calculator)

 

enter 
as      x - 3/2
enter (x - 3)/2 order of operations
13 equation: x2 = 9
solution:  x =  = 3
 solution: x =   3  
14

 

  -12 = 1  -12 = -1  order of operations.  (-1) 2 = 1
15

 

subtract a + b from x as follows:
x - (a + b)  =  x - a + b
 =  x - a - b  distribute the "-" sign to all terms in (a + b)

* not wrong, just inefficient/immature form for students doing college-level algebra