Toán tìm x a,84-4.(2.x+1)=48 b,1230:3(x-20)=10 tính các tổng sau: A=100+98+96+…+2-99-97-…-1 B=1+2-3-4+5+6-7-8+…-299-300+301+302 22/07/2021 By Bella tìm x a,84-4.(2.x+1)=48 b,1230:3(x-20)=10 tính các tổng sau: A=100+98+96+…+2-99-97-…-1 B=1+2-3-4+5+6-7-8+…-299-300+301+302
a, 84 – 4.(2x + 1) = 48 4.(2x + 1) = 84- 48 4.(2x + 1) = 36 2x + 1 = 36: 4 2x + 1 = 9 2x = 9- 1 2x = 8 x = 8 : 2 x = 4 b,1230: 3(x- 20) = 10 410 (x – 20) = 10 x – 20 = 410 : 10 x – 20 = 41 x = 41 + 20 x = 61 Trả lời