Đáp án:
C1:
`3x^2+13x-10`
`=3x^2-2x+15x-10`
`=x(3x-2)+5(3x-2)`
`=(3x-2)(x+5)`
C2:
`3x^2+13x-10`
`=3(x^2+(13)/3 x-(10)/3)`
`=3(x^2+2.(13)/6 .x+(169)/36-(289)/36)`
`=3[(x+(13)/6)^2-(289)/36]`
`=3[(x+(13)/6)^2-((17)/6)^2]`
`=3(x+(13)/6+(17)/6)(x+(13)/6-(17)/6)`
`=3(x+(30)/6)(x-2/3)`
C3:
`3x^2+13x-10`
`=(3x²+ 15x )-(2x + 10 )`
`=3x(x+5)-2(x+5)`
`=(x+5)(3x-2)`