Which function has real zeros at x = 3 and x = 7?

f (x) = x2 + 4x - 21

O f (x) = x2 - 4x - 21

O f (x) = x2 - 10x + 21

O f (x) = x2 - 10x - 21

all of them will give u zero

but not all of them

in the first one only if you equate x to be 3 that is when it will give u zero

for the second one is only when u equate x to be seven that's when it will be equal to zero

the same thing for the rest!