A²+b² = 15 dan a+b = 5 maka nilai 2a-2b ? ​

a² + b² = 15

(a + b)² – 2ab = 15

(5)² – 2ab = 15

25 – 2ab = 15

– 2ab = 15 – 25

– 2ab = -10

2ab = 10

ab = 5

.

a² + b² = 15

(a – b)² + 2ab = 15

(a – b)² + 2(5) = 15

(a – b)² + 10 = 15

(a – b)² = 15 – 10

(a – b)² = 5

a – b = √5

.

2a – 2b

= 2(a – b)

= 2(√5)

= 2√5