The equation is .
Apply addition property of equality: Add to each side.
(Apply additive inverse property:
)
Apply addition property of equality: Add to each side.
Apply commutative property of addition: a + b = b + a.
\ (Apply additive inverse property:
)
To add the fractions denominator must be equal.
\Find the least common denominator (LCD).
\Multiples of 4: 4,8,12,16,20,24,28,32,......
\Multiples of 7: 7,14,21,28,35,.......
\The least common multiple of 4 and 7 is 28.
\Rewrite each fraction with a common denominator of 28.
\ and
(LCM is 28)
(Add: 21 + 12 = 33)
Apply multiplication property of equality: Multiply each side by 2.
\ (Cancel common terms)
(Multiply:
)
(Divide:
)
Check:
\To check the solution, substitute in original equation.
(Multiply:
)
(Multiply:
)
\ \
(
)
(LCM is 28)
(Subtract: 21
33 =
12)
(Divide:
)
Compare the values, the equation is true.
The value of b is .