A= 2x + 6x + 3 x^2+xy x^2-y^2 y-x Ai giúp mình vs đây là phân số nhá! mìnhcamonn 25/11/2021 Bởi Claire A= 2x + 6x + 3 x^2+xy x^2-y^2 y-x Ai giúp mình vs đây là phân số nhá! mìnhcamonn
Đáp án: `A = 5/(x + y)` Giải thích các bước giải: `A = (2x)/(x^2 + xy) + (6x)/(x^2 – y^2) + 3/(y – x)` ` = (2x)/[x(x + y)] + (6x)/[(x + y)(x – y)] + (-3)/(x – y)` `= [2x(x – y)]/[x(x + y)(x – y)] + (6x.x)/[x(x + y)(x – y)] + [(-3).x(x + y)]/[x(x + y)(x – y)]` `= [2x(x – y) + 6x^2 + (-3x)(x + y)]/[x(x + y)(x – y)] = [2x^2 – 2xy + 6x^2 + (-3x^2 – 3xy)]/[x(x + y)(x – y)]` `= [2x^2 – 2xy + 6x^2 – 3x^2 – 3xy]/[x(x + y)(x – y)] = [5x^2 – 5xy]/[x(x + y)(x – y)] = [5x(x – y)]/[x(x + y)(x – y)] = 5/(x + y)` Bình luận
` A = \frac{2x}{x^2 + xy} + \frac{6x}{x^2 – y^2} + \frac{3}{y – x} ` ` => A = \frac{2x(x – y) + 6x . x – 3x(x + y)}{x(x – y)(x + y)} ` ` => A = \frac{2x^2 – 2xy + 6x^2 – 3x^2 – 3xy}{x(x – y)(x + y)} ` ` => A = \frac{5x^2 – 5xy}{x(x – y)(x + y)} ` ` => A = \frac{5x(x – y)}{x(x – y)(x + y)} ` ` => A = \frac{5}{x + y} ` Bình luận
Đáp án:
`A = 5/(x + y)`
Giải thích các bước giải:
`A = (2x)/(x^2 + xy) + (6x)/(x^2 – y^2) + 3/(y – x)`
` = (2x)/[x(x + y)] + (6x)/[(x + y)(x – y)] + (-3)/(x – y)`
`= [2x(x – y)]/[x(x + y)(x – y)] + (6x.x)/[x(x + y)(x – y)] + [(-3).x(x + y)]/[x(x + y)(x – y)]`
`= [2x(x – y) + 6x^2 + (-3x)(x + y)]/[x(x + y)(x – y)] = [2x^2 – 2xy + 6x^2 + (-3x^2 – 3xy)]/[x(x + y)(x – y)]`
`= [2x^2 – 2xy + 6x^2 – 3x^2 – 3xy]/[x(x + y)(x – y)] = [5x^2 – 5xy]/[x(x + y)(x – y)] = [5x(x – y)]/[x(x + y)(x – y)] = 5/(x + y)`
` A = \frac{2x}{x^2 + xy} + \frac{6x}{x^2 – y^2} + \frac{3}{y – x} `
` => A = \frac{2x(x – y) + 6x . x – 3x(x + y)}{x(x – y)(x + y)} `
` => A = \frac{2x^2 – 2xy + 6x^2 – 3x^2 – 3xy}{x(x – y)(x + y)} `
` => A = \frac{5x^2 – 5xy}{x(x – y)(x + y)} `
` => A = \frac{5x(x – y)}{x(x – y)(x + y)} `
` => A = \frac{5}{x + y} `