Select all expressions that are equivalent to 0.75x + 0.25(x + 12.4) + (x – 2.1)
A. 2x + 1
B. x + 1
C. x + 3.1 + x + 2.1
D. x + 3.1 + x – 2.1

Please tell me what to do. I am in need of help. Thank you!!

Both    A.)  2x + 1   and  D.) x + 3.1 + x – 2.1

The question says select all equivalent expressions

Step-by-step explanation:

0.75x + 0.25(x + 12.4) + (x – 2.1)  

distribute 0.25 in the middle term 0.25 × 12.4 = 3.1

and "multiply by +1" the second parentheses to remove them

0.75x + 0.25x + 3.1 + x – 2.1  

add the decimal coefficients  0.75x + 0.25x = 1.00x (means 1x) so:  = x

x + 3.1 + x - 2.1    This is choice D  an equivalent expression

simplify by combining like terms to get

2x + 1   This is choice A

step-by-step explanation: