Step-by-step explanation:
Area of square
A = s²
A = 28²
A = 28 × 28
A = 784 cm²
Simply distribute the -3 across the b and -7.
-3(b - 7) = (-3 * b) + (-3 * -7) = -3b + 21
Hope this was helpful, if it wasn't just drop me a DM explaining what didn't make sense.
