Answer:
4/9ths of a cup of sugar is needed for one cup of flour.
Step-by-step explanation:
To answer this you need to scale the number of cups of flour up from 3/4 to 1 that ratio would be 4/3 (multiplying a fraction by its own reciprocal will give you 1).
We can then simply take that ratio, and scale the sugar by the same amount:
1/3 * 4/3 = 4/9
3r-6=-21
3r-6+6=-21+6 (Add 6 to both sides...)
3r=-15
r=-5
3r-6=21
3r-6+6=21+6 (Add 6 to both sides...)
3r=27
r=9
r=-5 or r=9
After you do the distributive property, it would be -21n-3