Tìm x, biết a) (2x+5)² = (x+2)² b) 4(x-2)² = 25(1-2x)² Thks mọi người :3 07/12/2021 Bởi Alexandra Tìm x, biết a) (2x+5)² = (x+2)² b) 4(x-2)² = 25(1-2x)² Thks mọi người :3
Bài lm nek Nhớ vote cho mk 5 sao nhé ???? a) (2x + 5)² = (x + 2)² -> (2x + 5)² – (x + 2)² = 0 -> (2x + 5 + x + 2)(2x + 5 – x – 2) = 0 -> (3x + 7)(x + 3) = 0 -> 3x + 7 = 0 hoặc x + 3 = 0 -> x = -7/3 hoặc x = -3 b) 4(x – 2)² = 25 (1 – 2x)² -> 4(x – 2)² – 25 (1 – 2x)² = 0 -> 4(x – 2)² – 25 (2x – 1)² = 0 -> [2 (x – 2)]² – [5 (2x – 1)]² = 0 -> (2x – 4)² – (10x – 5)² = 0 -> (2x – 4 + 10x – 5)(2x – 4 – 10x + 5) = 0 -> (12x – 9)(1 – 8x) = 0 -> 12x – 9 = 0 hoặc 1 – 8x = 0 -> x = 3/4 hoặc x = 1/8 Bình luận
Bài lm nek
Nhớ vote cho mk 5 sao nhé ????
a) (2x + 5)² = (x + 2)²
-> (2x + 5)² – (x + 2)² = 0
-> (2x + 5 + x + 2)(2x + 5 – x – 2) = 0
-> (3x + 7)(x + 3) = 0
-> 3x + 7 = 0 hoặc x + 3 = 0
-> x = -7/3 hoặc x = -3
b) 4(x – 2)² = 25 (1 – 2x)²
-> 4(x – 2)² – 25 (1 – 2x)² = 0
-> 4(x – 2)² – 25 (2x – 1)² = 0
-> [2 (x – 2)]² – [5 (2x – 1)]² = 0
-> (2x – 4)² – (10x – 5)² = 0
-> (2x – 4 + 10x – 5)(2x – 4 – 10x + 5) = 0
-> (12x – 9)(1 – 8x) = 0
-> 12x – 9 = 0 hoặc 1 – 8x = 0
-> x = 3/4 hoặc x = 1/8