Which is a factor of 144 - 49x2?

12 - 7x2

72 - 7x2

12 - 7x

72 + 7x

Answer is C

(12-7x)

Step-by-step explanation:

144 - 49x²

by observation, we can see that 144 = 12² and 49 = 7²

hence we can rewrite the equation

144 - 49x²

= 12² - 7²x²

= 12² - (7x) ²

recall that the expression x² - y² = (x+y) (x-y)

hence,

12² - (7x) ²

= (12 + 7x) (12-7x)

(12-7x) appears in the expression above, hence 12 - 7x is a factor