How do you solve -6.5b + 8.5+ 3b = 27.5−6.5b+8.5+3b=27.5?

2 Answers
Jess
Jan 15, 2018

As with any algebraic equation, clump the variables on one side (it is preferable if the coefficient of the variable is positive, but it doesn't really matter).

-6.5b+8.5+3b=27.5−6.5b+8.5+3b=27.5
-3.5b=19−3.5b=19
b=19/-3.5b=19−3.5
b=-5.43b=−5.43 (3s.f.)

Tony B
Jan 15, 2018

b=-38/7b=−387
The question does not state that we may use an approximate answer (rounding a decimal). You may or may not loose marks in an exam. Risky!

Explanation:

Don't like decimals so lets get rid of them.

Multiply both sides by 10

-65b+85+30b=275−65b+85+30b=275

Regrouping:

(30b-65b)+85=275(30b−65b)+85=275

color(white)("d")-35b color(white)("dddd") +85=275d−35bdddd+85=275

Subtract 85 from both sides

-35b=+190−35b=+190

Note that when dividing, if the signs are the same, the result is positive.

Divide both sides by (-35)(−35)

+b=(+190)/(-35)+b=+190−35

b=-38/7color(red)( larr" More precise than a rounded decimal")b=−387← More precise than a rounded decimal

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