Jawabanmu

2014-08-29T00:17:14+07:00
A. 2√3 (2√40+√12)
=2√3×2√40 + 2√3×√12
=4√120 + 2√36
=4√4×√30 + 2√9×√4
=4×2×√30 + 2×3×2
=8√30+12 --> disederhanakan dengan dibagi 4
=2√30+3

b.(√2+√5)(√2-√5)
=(a+b)(a-b)
=a²-b²
=(√2)² - (√5)²
=2-5
=-3

c.(2√5-3√3)(3√5+3√3)
=2√5×3√5 + 2√5×3√3 - 3√3×3√5 - 3√3×3√3
=6√25 + 6√15 - 9√15 - 9√9
=6×5 - 3√15 - 9×3
=30 - 27 - 3√15
=3 - 3√15
=1-√15

d.(4√7)² - (2√3)²
= 4²×(√7)² - 2²×(√3)²
=16×7 - 4×3
=112-12
=100