whatsz 4(x+5.1)-5x

It is an algebraic expression.

To simplify the algebraic expression 4(x + 5.1) - 5x, let's follow the order of operations (PEMDAS/BODMAS) which states that you should solve parentheses first, then exponents, then multiplication and division (from left to right), and finally addition and subtraction (from left to right).

1. Distribute the 4 to each term inside the parentheses:
4(x + 5.1) - 5x = 4x + (4 * 5.1) - 5x

2. Multiply:
4x + (4 * 5.1) - 5x = 4x + 20.4 - 5x

3. Combine like terms:
4x - 5x + 20.4 = (-x) + 20.4

Therefore, the simplified form of the expression 4(x + 5.1) - 5x is -x + 20.4.