R=-7, you have to put each answer in the equation, therefore; 21=42-3(-7) So you have to do multiplication (PEMDAS, if you arent aware of that acronym then it stands for the order of what to do with an equation, Parentheses get solved first, then Exponents, then multiplication, then division, then addition, then finally subtraction. Solving in that order will solve your answer correctly.) With -3 times -7 which gives you 21. Then you do 42 - 21 which equals 21. So 21 = 21.
I think it's 85 but Is this like a multiple choice question?
Answer:
Undefined
Step-by-step explanation:
has a slope of 
, since it is a horizontal line. The only types of lines that are perpendicular to horizontal lines are vertical lines, which are usually in the form 
(where 
is any real number). Vertical lines have an undefined slope, so the answer is undefined. Hope this helps!
Answer:
Step-by-step explanation:
![\sqrt[12]{2}](https://tex.z-dn.net/?f=%20%5Csqrt%5B12%5D%7B2%7D%20)
