Question

已知│a-1│+(2a-b) 2=0,那么3ab–15b 2-6ab+15a-2b 2等于_______.

Answer 1

∵│a-1│+(2a-b) ²=0
∴a=1 2a-b=0
∴b=2

3ab–15b²-6ab+15a-2b²
=-3ab-17b²+15a
=-3*1*2-17*4+15*1
=-6-68+15
=-59
【俊狼猎英】团队为您解答

Answer 2

解：∵ 丨a - 1丨+ （2 a - b）² = 0
又∵ 丨a - 1丨≥ 0
（2 a - b）² ≥ 0
∴ a - 1 = 0
2 a - b = 0
∴ a = 1
2 × 1 - b = 0
b = 2
∴ 3 a b - 15 b ² - 6 a b + 15 a - 2 b ²
= （3 - 6）a b + （- 15 - 2）b ² + 15 a
= - 3 a b - 17 b ² + 15 a
= - 3 × 1 × 2 - 17 × 2 ² + 15 × 1
= - 6 - 17 × 4 + 15
= 9 - 68
= - 59

【俊狼猎英】团队为您解答

Answer 3

│a-1│+(2a-b) 2=0
所以a-1=2a-b=0
所以a=1,b=2
所以3ab–15b 2-6ab+15a-2b 2=3*2-15*4-6*2+15-2*4=6-60-12+15-8=-59