Sederhanakanlah. a.(2akar3-6akar7) (4akar5+akar7) b.(7akar3+akar8) (6akar3-5) c.(7akar2-akar5) (2akar2+akar5)

a.
(2√3 - 6√7)(4√5 + √7)
=(2√3 × 4√5) + (2√3 × √7) - (6√7 × 4√5) - (6√7 × √7)
=8√15 + 2√21 - 24√35 - 6√49
=8√15 + 2√21 - 24√35 - 6×7
=8√15 + 2√21 - 24√35 - 42

b.
(7√3 + √8)(6√3 - 5)
=(7√3 × 6√3) - (7√3 × 5) + (√8 × 6√3) - (√8 × 5)
=42√9 - 7√15 + 6√24 - 5√8
=42×3 - 7√15 + 6√4×6 - 5√4×2
=126 - 7√15 + 6×2√6 - 5×2√2
=126 - 7√15 + 12√6 - 10√2

c.
(7√2 - √5)(2√2 + √5)
=(7√2 × 2√2) + (7√2 × √5) - ( √5 × 2√2) - (√5×√5)
=14√4 + 7√10 - 2√10 - √25
=14×2 + 5√10 - 25
=28 + 5√10 - 25

Semoga bisa membantu...