# Urgent Help

• Jun 18th 2005, 01:36 PM
Hayabusa
Urgent Help
Hey guys can you please help me with these two problems? I just do not understand how to do them, I don't know where to begin!

Find each value if g(x) = 2x + 3 and h(x) = x/2-7

Find: G(9)

Find: H(4)
• Jun 18th 2005, 06:32 PM
Math Help
Substitution
This type of problem is an exercise in substituting a value (such as 9) for a variable (such as x).

1. Find: G(9) if G(x) = 2x + 3

we replace x with 9 in the above equation so:

G(9) = 2*9+3 .........|replace x with 9
G(9) = 18+3 ...........|multiplacation before addition (PEMDAS)
G(9) = 21

Try to do the second one here as a reply and I will correct you.
• Jun 19th 2005, 07:24 AM
Hayabusa
So for problem: H(4)

H(4)= 4/2-7

4/-5

= -0.8

Please correct me if I am wrong.
• Jun 19th 2005, 08:12 AM
Nicol
h(x) = x/2-7
Find: H(4)

Don't forget the order of operations. First you devide then you subtract. So you have:

$\displaystyle H(4) = \frac{4}{2} -7$

$\displaystyle H(4) = 2 -7$

$\displaystyle H(4) = -5$
• Jun 19th 2005, 08:24 AM
Hayabusa
Thank you for your help. I appreciate it very much :D
• Jun 19th 2005, 08:52 AM
MathGuru
Order of Operations
Regarding order of operations:

Remember PEMDAS

Parentheses
Exponents
Multiplication
Division