a) 150 - [70 - (7 - 4)2]
= 150 - [70 - 32]
= 150 - [70 - 9]
= 150 - 61
= 89.
b, 2 . 52 + 72 . 34 - 72 . 33
= 2 . 25 + 49 . 81 - 49 . 9
= 2 . 25 + [49 . (81 - 9)]
= 50 + [49 . (81 - 9)]
= 50 + [ 49 . 72]
= 50 + 3528
= 3578.
a, 150 - [ 70 - ( 7 - 4 ) mu2
= 150 - [ 70 - 3 mu2 ]
= 150 - [ 70 - 9 ]
= 150 - 6
= 114