jika 3m(am+4)=15m³+bm, nilai dsri ab(a+b)??? A.1.200 B.1.020 C.420 D.289 ps=harus pake cara lengkapp

Bab Persamaan Kuadrat
Matematika SMP Kelas VIII

3m (am + 4) = 15m² + bm
3am² + 12m = 15m² + bm

3a = 15
a = 5

12 = b
b = 12

a . b (a + b) = 5 . 12 . (5 + 12)
                   = 60 . 17
                   = 1.020

jawabannya B

Persamaan Kuadrat

3m(am + 4) = 15m² + bm
3am² + 12m = 15m² + bm

Perhatikan kesamaan tempat nya
3am² = 15m²
3a = 15
a = 5 ✔

12m = bm
b = 12 ✔

••
ab(a + b)
= (5 × 12)(5 + 12)
= 60 × 17
= 1020 ✔✔