Respuesta :

choixongdong
a^2 - b^2 ...difference of squares

so
9m^4 - 49n^6 = (3n^2)^2 - (7n^3)^2

answer
C. 9m^4 - 49n^6 
The answer would be C because the coefficients are both perfect squares and when you subtract the exponents (6 - 4), it turns up to be an even number. (difference of exponents have to be an even number or zero)