Respuesta :

Catya
Difference means subtraction (-)
Twice a number means × 2
is at least ≥

Put it all together
2b - 9 ≥ -15

Then you can solve for b
2b - 9 ≥ -15
2b ≥ -15 + 9
2b ≥ - 6
b ≥ - 6/2
b ≥ - 3