# Thread: name the restrictions for each expression

1. ## name the restrictions for each expression

all I can say is help lol if some one could please show me the work and answer I think I will be able to finish the rest of my problems like this thanks in advance
#1

x^2+5x-7
_________

2-x

#2

t^2+4t+4
_________

t^2-16

all I can say is help lol if some one could please show me the work and answer I think I will be able to finish the rest of my problems like this thanks in advance
#1

x^2+5x-7
_________

2-x

#2

t^2+4t+4
_________

t^2-16
Can the denominator of any expression be 0?

-Dan

all I can say is help lol if some one could please show me the work and answer I think I will be able to finish the rest of my problems like this thanks in advance
#1

x^2+5x-7
_________

2-x

#2

t^2+4t+4
_________

t^2-16
1.)

$\displaystyle \frac{x^2+5x-7}{2-x}$, $\displaystyle x \not= 2$

2.)

$\displaystyle \frac{t^2+4t+4}{t^2-16}$ $\displaystyle =$ $\displaystyle \frac{(t+2)^2}{(t+4)(t-4)}$, $\displaystyle t \not= \pm 4$

4. I do not htink they could be zero is the answer as simple as that zero?

5. how did u get the 2 and the +or- 4

how did u get the 2 and the +or- 4
As if you have $\displaystyle t = \pm 4$ then one bracket becomes zero hence when you times the other bracket, your whole denominator becomes zero which is not allowed.

7. so then that means in the first one it can not be 2 because 2-2 =0 so thats is why 2 can not equal x?

so then that means in the first one it can not be 2 because 2-2 =0 so thats is why 2 can not equal x?
Right. It's that simple.

-Dan