Questions on Algebra: Evaluation of expressions, parentheses answered by real tutors!

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Question 149955This question is from textbook
: I am totatly lost with evaluating please help.
problem: 26) 2/3 ab, for a = 7 and b = 4 1/5
27) 4 + mn, for m = 7 2/5 and n = 3 1/4This question is from textbook
: I am totatly lost with evaluating please help.
problem: 26) 2/3 ab, for a = 7 and b = 4 1/5
27) 4 + mn, for m = 7 2/5 and n = 3 1/4
Answer by jim_thompson5910(9376) About Me  (Show Source):
You can put this solution on YOUR website!
# 26

First convert the mixed number b=4&1/5 into the improper fraction b=21/5 note: let me know if you need help with fraction conversion.


(2/3) ab Start with the given expression.


(2/3)(7)(21/5) Plug in a=7 and b=21/5


(2*7*21)/(3*5) Combine the fractions



(2*7*3*7)/(3*5) Factor 21 into 3*7


(2*7*highlight(3)*7)/(highlight(3)*5) Highlight the common terms.



(2*7*cross(3)*7)/(cross(3)*5) Cancel the common terms.


(2*7*7)/(5) Simplify


(98)/(5) Multiply 2, 7, and 7 to get 98



So (2/3) ab=(98)/(5) when a=7 and b=21/5


If you want the approximate answer, then (2/3) ab=19.6 when a=7 and b=21/5







First convert the mixed number m = 7&2/5 into the improper fraction 37/5. Also, convert the mixed number n = 3&1/4 into the improper fraction n=13/4



4 + mn Start with the given expression.


4 + (37/5)(13/4) Plug in a=37/5 and b=13/4


4 + (37*13)/(5*4) Combine the fractions.


4 + (481)/(5*4) Multiply 37 and 13 to get 481


4 + (481)/(20) Multiply 5 and 4 to get 20



4(20/20)+(481)/(20) Multiply 4 by 20/20.


80/20+481/5 Combine and multiply the fractions.



561/20 Add the fractions.


So 4 + mn=561/20 when a=37/5 and b=13/4



If you want the approximate answer, then 4 + mn=28.05 when a=37/5 and b=13/4