What's negative three over four plus one and two over seven

2 1/28

Step-by-step explanation:

Multiply both the numerator and denominator of each fraction by the number that makes its denominator equal the LCD. This is basically multiplying each fraction by 1.

(3/4*7/7) + (9/7*4/4) = ?

Complete the multiplication and the equation becomes

21/28+36/28=?

The two fractions now have like denominators so you can add the numerators.

Then:

21+36/28=57/28=2 1/28