How would you solve:

3.5r squared minus 5.5 + 1.5r squared plus 4?

(3.5 r^2) -5.5 +1.5r^2 +4?

That can be simplified to
5 r^2 -1.5

(3.5r)^2 or 3.5 r^2 ???

We really need parentheses to see what you mean. I suspect you mean it as
3.5 r^2 -5.5 +1.5 r^2 + 4
you add and subtract like terms, for example you have 3.5 r^2 + 1.5 r^2 which is 5 r^2
and you have 5.5 + 4 = 9.5

and you have -5.5 + 4 = -1.5

To solve the given expression involving quadratic terms, we need to combine like terms and simplify the expression. Here are the steps to solve it:

1. Group the terms with the same variable together:
Start with the given expression: 3.5r^2 - 5.5 + 1.5r^2 + 4.
Group the terms with r^2: (3.5r^2 + 1.5r^2) - 5.5 + 4.

2. Simplify the terms:
Combine the like terms: (3.5 + 1.5)r^2 - 5.5 + 4.
This simplifies to: 5r^2 - 5.5 + 4.

3. Simplify further:
Combine the constants: -1.5 + 4 = 2.5.
The expression now becomes: 5r^2 - 1.5.

So, the solution to the expression 3.5r^2 - 5.5 + 1.5r^2 + 4 is 5r^2 - 1.5.