Simplify: 2x-5 - ([x-8]/[x+4])?
回答 (3)
2016-08-21 2:45 am
2x − 5 − ([x − 8]/[x + 4])
∴ [2x − 5] × ([x + 4]/[x + 4]) − ([x − 8]/[x + 4])
∴ ([2x² + 8x − 5x − 20]/[x + 4]) − ([x − 8]/[x + 4])
∴ ([2x² + 3x − 20]/[x + 4]) − ([x − 8]/[x + 4])
∴ ([2x² + 3x − 20] − [x − 8])/[x + 4]
∴ [2x² + 3x − 20 − x + 8]/[x + 4]
∴ [2x² + 2x − 12]/[x + 4] <== Simplified
(2[x + 3][x − 2])/[x + 4] <== Factored
∴ [2x − 5] × ([x + 4]/[x + 4]) − ([x − 8]/[x + 4])
∴ ([2x² + 8x − 5x − 20]/[x + 4]) − ([x − 8]/[x + 4])
∴ ([2x² + 3x − 20]/[x + 4]) − ([x − 8]/[x + 4])
∴ ([2x² + 3x − 20] − [x − 8])/[x + 4]
∴ [2x² + 3x − 20 − x + 8]/[x + 4]
∴ [2x² + 2x − 12]/[x + 4] <== Simplified
(2[x + 3][x − 2])/[x + 4] <== Factored
2016-08-21 5:51 am
2x - 5 - ([x - 8]/[x + 4])
= [(2x - 5)(x + 4) - (x - 8)]/(x + 4)
= (2x^2 + 2x - 12)/(x + 4)
= [2(x + 3)(x - 2)]/(x + 4)
= [(2x - 5)(x + 4) - (x - 8)]/(x + 4)
= (2x^2 + 2x - 12)/(x + 4)
= [2(x + 3)(x - 2)]/(x + 4)
2016-08-21 4:56 am
Simplify: 2x-5 - ([x-8]/[x+4])
multiply by lcm, which is x+4
((2x-5)(x+4) - (x-8))/(x+4)
(2x^2 + 3x - 20 - x + 8)/(x+4)
(2x^2 + 2x - 12)/(x+4)
(2x^2 + 6x - 4x - 12)/(x+4)
(2x(x+3) -4(x+3))/(x+4)
((2x-4)(x+3))/(x+4)
multiply by lcm, which is x+4
((2x-5)(x+4) - (x-8))/(x+4)
(2x^2 + 3x - 20 - x + 8)/(x+4)
(2x^2 + 2x - 12)/(x+4)
(2x^2 + 6x - 4x - 12)/(x+4)
(2x(x+3) -4(x+3))/(x+4)
((2x-4)(x+3))/(x+4)
參考: year 10 student, taught in the beginning of year 9.
收錄日期: 2021-04-21 19:40:42
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https://hk.answers.yahoo.com/question/index?qid=20160820182527AAsU71V