a) 2(x+1)2-(x-3)(x+3)-(x-4)2 = 0
=> 2.(x2+2x+1)-(x2-9)-(x2-8x+16) = 0
=> 2x2+4x+2-x2+9-x2+8x-16 = 0
=> 12x-5 = 0
=> 12x = 0+5
=> 12x = 5
=> x = 5:12
=> x = \(\frac{5}{12}\)
b) (x-5)2-x.(x-1) = 9
=> x2-10x+25-x2+x = 9
=> -9x+25 = 9
=> -9x = 9-25
=> -9x = -16
=> x = -16:-9
=> x = \(\frac{16}{9}\)
bạn tư làm mấy câu còn lại nha
câu b mình quên ghi mũ, xin lỗi, mong bạn đọc hiểu cho
ban quen ghi mu o doan (x-5)-x.(x-1)=9
x^2-10x+25-x+x=9 phai ko ban
c) (x-5)2+(x-4).(1-x) = 0
=> x2-10x+25+x-x2-4+4x = 0
=> -5x+21 = 0
=> -5x = 0-21
=> -5x = -21
=> x = -21:-5
=> x = \(\frac{21}{5}\)
d) (x-2)3+6.(x+1)2-x3+12 = 0
=> x3-6x2+12x-8+6x2+12x+6-x3+12 = 0
=> 24x+10 = 0
=> 24x = 0-10
=> 24x = -10
=> x = -10:24
=> x \(\frac{-5}{12}\)