It's very important to evaluate these expressions following order of operations (PEMDAS ) rules.
Any work inside parentheses must be done first.
Multiply and divide before adding or subtracting.
Thus, 75 - (5*1 + 4) = 75 - (9) = 66
2nd expression: 75 - 5*(1 + 4) = 75 - 5(5) = 50
3rd expression: (75 - 5)*(1 + 4) = 70*5 = 350
4th expression: (75 - 5)*1 + 4 = 70 + 4 = 74 This one is correct.
