Toán `(36x-x^3)/(x^3+12x^2+36x)=A/(6+x)` Tìm `A` 24/11/2021 By Jade `(36x-x^3)/(x^3+12x^2+36x)=A/(6+x)` Tìm `A`
Đáp án: `(36x-x^3)/(x^3+12x^2+36x)=A/(6+x)` `=> (6+x)(36x-x^3)=A.(x^3+12x^2+36x)` `=> [(6+x)(36x-x^3)] : (x^3+12x^2+36x)=A` `=> [(6+x).x.(36-x^2)] : [x.(x^2+12x+36)]=A` `=> [x.(6+x).(6-x).(6+x)] : [x. (x+6)^2]=A` `=> [x.(6+x)^2. (6-x)] : [x. (x+6)^2]=A` `=> 6-x=A` Vậy `A=6-x` Trả lời
Đáp án: Ta có `(36x – x^3)/(x^3 + 12x^2 + 36x) = A/(6 + x)` `<=> A = (36x – x^3)/(x^3 + 12x^2 + 36x) . (x + 6)` `<=> A = [(36x – x^3)(x + 6)]/(x^3 + 12x^2 + 36x) ` `<=> A = [-(x^3 – 36x)(x + 6)]/[x(x^2 + 12x + 36)]` `<=> A = [-x(x^2 – 36)(x + 6)]/[x(x + 6)^2]` `<=> A = [-x(x – 6)(x + 6)^2]/[x(x + 6)^2]` `<=> A = 6 – x` Giải thích các bước giải: Trả lời
Đáp án:
`(36x-x^3)/(x^3+12x^2+36x)=A/(6+x)`
`=> (6+x)(36x-x^3)=A.(x^3+12x^2+36x)`
`=> [(6+x)(36x-x^3)] : (x^3+12x^2+36x)=A`
`=> [(6+x).x.(36-x^2)] : [x.(x^2+12x+36)]=A`
`=> [x.(6+x).(6-x).(6+x)] : [x. (x+6)^2]=A`
`=> [x.(6+x)^2. (6-x)] : [x. (x+6)^2]=A`
`=> 6-x=A`
Vậy `A=6-x`
Đáp án:
Ta có
`(36x – x^3)/(x^3 + 12x^2 + 36x) = A/(6 + x)`
`<=> A = (36x – x^3)/(x^3 + 12x^2 + 36x) . (x + 6)`
`<=> A = [(36x – x^3)(x + 6)]/(x^3 + 12x^2 + 36x) `
`<=> A = [-(x^3 – 36x)(x + 6)]/[x(x^2 + 12x + 36)]`
`<=> A = [-x(x^2 – 36)(x + 6)]/[x(x + 6)^2]`
`<=> A = [-x(x – 6)(x + 6)^2]/[x(x + 6)^2]`
`<=> A = 6 – x`
Giải thích các bước giải: