Order of Operations question

[pmcheng]

The math teacher and I got different answers for the following equation -(-4exp2)+ [(-8-6-(18)]. I got -12, she got 20. Please tell me how to solve this equation.

Thanks,

 

[soroban]

Hello, pmcheng!

I think you dropped a minus-sign.

The math teacher and I got different answers for the following equation
. . \(\displaystyle -(-4^2)+ [(-8-6-({\color{red}-}18)]\)

I got -12, she got 20.
Please tell me how to solve this equation.

Careful . . . we don't have an equation; just an expression.


We must be very careful with that first term.

Note that: .\(\displaystyle -4^2 \:=\: -(4^2) \:=\:-16\)

So we have: .\(\displaystyle -(-16) + (-8 -6 + 18) \:=\:16 + 4 \:=\:20\)


The "minus" is not squared!
If they wanted the "minus" squared, they must write: \(\displaystyle (-4)^2\)

 

[pmcheng]

Hi Soroban,

Thanks so much for help! I now understand how she got her answer.