A.) To find the perimeter, add two lengths and two widths.
length= 3x+7
width= 2x-3
3x+7+3x+7+2x-3+2x-3
Combine like terms
you end up with an expression like this:
14x+8 cm
B.) Plug in 4 for x into the new expression:
14(4)+8
perimeter=64 cm
C.)When multiplying polynomials, it's just like normal multiplication, except remember to add the exponents.
3x*2x=6x^2
7*-3= -21
So, the new expression is:
6x^2-21 cm squared
D.) Again, plug in the 4 for x.
6(4^2)-21
4*4=16
16*6=96
96-21=75
Area=75 cm squared
E.) If the length is 5 cm longer:
Remember, the length is 3x+7
So, just add 5 to the expression.
7+5=12
The new expression is:
3x+12
Then, add that like you did before.
3x+12+3x+12+2x-3+2x-3
New expression:
Perimeter=10x+18 cm
