Question

Aljabar
Jika a = 2 dan b = -5, tentukan nilai masing-masing berikut!
a. 2a + 4b - a + 7b
b. 2ab - 3a + 4b - 3ab
c. -3a²b² + ab + 2a²b² - 5ab
d. a(a + b) - b(a + b)

Answer 1

A. 2×2 + 4×(-5) -2 + 7×(-5)
= 4 + (-20) - 2 + (-35)
= 4+ (-22) + (-35)
= 4+ (-57)
=-53

b. 2×2×(-5) - 3×2 + 4×(-5) - 3×2×(-5)
= (-20) - 6 + (-20) - (-30)
= -16

c. -3×2^2×-5^2 + 2×-5 + 2×2^2×-5^2 - 5×2×-5
= -3×4×25 + -10 + 2×4×25 - (-50)
= -300 + -10 + 200 - (-50)
= -105

d. 2(2+(-5)) - -5(2+(-5))
= 2×2 + 2×-5 - (-5)×2 + (-5)×(-5)
= 4 + -10 - (-10) + 25
= 29

semoga membantu^^

Answer 2

A) 2a + 4b - a + 7b
2(2) + 4(-5) -(2) +7(-5)
4 - 20 - 2 -35
-53

b) 2ab - 3a + 4b - 3ab
2(2)(-5) -3(2) + 4(-5) - 3(2)(-5)
-20 - 6 -20 + 30
-16

c) -3a²b² + ab + 2a²b² - 5ab
-3(2)²(-5)² + (2)(-5) + 2(2)²(-5)² - 5(2)(-5)
-300 - 10 + 200 + 50
-60

d) a(a + b) - b(a + b)
2(2 + (-5)) - (-5)(2+(-5))
4 - 10 + 10 + 25
29