Question

Matematika kelas 8 kur 2013 hal 55 latihan 2.3

Answer 1

1.
a) 2a × 2a = 4a^2
b) 3a × 3b = 9ab
c). (3s × 2s) + (3s × t) = 3s (2s + t)

2.
a). 10 × (2y - 10) = 20y - 100
b). (x + 5) × (5x - 1) = 5x^2 + 24x - 5
c). (7 - 2x) (2x - 7) = 14x - 49 - 4x² - 14x = -49 - 4x²

3.
(2x + 3y)(px + qy) = 2px² + 2xqy + 3pxy + 3qy²
= 2px² + (2q + 3p) xy + 3qy²

3py² = 12y²
p = 12y² / 3y²
p = 4

2px² = rx²
2(4)x² = rx²
8x² = rx²
r = 8