Answer:
(12-7x)
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