How do you solve #3= 7 (4-2u)-6u#?

2 Answers
Jim G.
Jun 20, 2018

#u=5/4#

Explanation:

#"distribute and simplify right side of equation"#

#3=28-14u-6u#

#3=28-20u#

#"subtract 28 from both sides"#

#3-28=-20u#

#-25=-20u#

#"divide both sides by "-20#

#(-25)/(-20)=urArru=5/4#

#color(blue)"As a check"#

Substitute this value into the right side of the equation and if equal to the left side then it is the solution.

#7(4-5/2)-15/2=21/2-15/2=6/2=3#

#u=5/4" is the solution"#

Bhavin B.
Jun 20, 2018

#u=5/4=1.25#

Explanation:

Open the brackets and simplify further:

#3=7(4-2u)-6u#

#3=(7 xx 4) - (7 xx 2u) - 6u#

#3=28-14u-6u#

#3=28-20u#

Subtract #28# both sides:

#3-28=28-28-20u#

#-25=cancel(28-28)-20u#

#-25=-20u#

Multiply by #-1# both sides to get rid of negative sign:

#-25 xx (-1) = -20u xx (-1)#

#25=20u#

Divide by #20# both sides:

#25/20 = (20u)/20#

#5/4=u#

Check the answer:

#3=7(4-2u)-6u#

#3=7(4-2(1.25))-6(1.25)#

#3=7(4-5/2)-15/2#

#3=7(4-2.5)-7.5#

#3=10.5-7.5#
#3=3#---> Correct!

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