Question

1
an expression is shown.
$-\frac{3}{7} + \frac{2}{3}$
what is the value of the expression?
a. $\frac{23}{21}$
b. $-\frac{23}{21}$
c. $\frac{5}{21}$
d. $-\frac{5}{21}$

Explanation:

Step1: Find common denominator

The least common denominator of 7 and 3 is 21. Rewrite fractions:
$-\frac{3}{7} = -\frac{3\times3}{7\times3} = -\frac{9}{21}$, $\frac{2}{3} = \frac{2\times7}{3\times7} = \frac{14}{21}$

Step2: Add the rewritten fractions

$\frac{-9 + 14}{21}$

Step3: Calculate numerator sum

$-9 + 14 = 5$

Answer:

C. $\frac{5}{21}$