1) 5√2 - 4√8 + 3√32 = 5√2 - 4√2*4 + 3√16*2 = 5√2 - 8√2 + 12√2 = -3√2 + 12√2 = 9√2
2) (√75 - √12)*√3 = √225 - √36 = 15 - 6 = 9
3) (√7 - 3)² = (√7)² - 2*3*√7 + 9 = 7 - 6√7 + 9 = 16 - 6√7
4) (√5 + 2√2)(√5 - 2√2) = (√5)² - (2√2)² = 5 - 4*2 = 5-8 = -3
