標題:
y=2(1-3y)-3 聯立方程
發問:
y=2(1-3y)-3 y=? 我係幫人問既... 佢話e d係叫聯立方程.. 更新: 仲有 x+3y=1 y=2x-3 更新 2: 求x同y..
最佳解答:
1) y=2(1-3y)-3 y = 2(1) - 2(3y) - 3 y = 2 - 6y - 3 y + 6y = 2 - 3 7y = -1 y = -1/7 2) x+3y=1 .... (1) y=2x-3 ... (2) 把(2)代入(1), x + 3(2x-3) = 1 x + 6x - 9 = 1 7x -9 = 1 7x = 10 x = 10/7 y = 2(10/7) - 3 = -1/7
1.y=2(1-3y)-3 y= 2-6y-3 7y=-1 y=-1/7 2.x+3y=1 ...(1) y=2x-3...(2) Put ' y=2x-3 ' into (1) x+3(2x-3)=1 7x-9=1 x=10/7 Put 'x=10/7' into (2) y=2(10/7)-3 y=20/14-3 y=-1/7|||||y=2(1-3y)-3 y=2-6y-3 y+3=2-6y 7y= -1 y= - 1/7 x+3y=1 ----1 y=2x-3 ----2 (2)----y=2x-3 -1/7=2x-3 -1/7 +3=2x 20/7 = 2x x = 40/7 SO: y= - 1/7 x = 40/7 唔知岩唔岩~太多年冇做
y=2(1-3y)-3 聯立方程
發問:
y=2(1-3y)-3 y=? 我係幫人問既... 佢話e d係叫聯立方程.. 更新: 仲有 x+3y=1 y=2x-3 更新 2: 求x同y..
最佳解答:
1) y=2(1-3y)-3 y = 2(1) - 2(3y) - 3 y = 2 - 6y - 3 y + 6y = 2 - 3 7y = -1 y = -1/7 2) x+3y=1 .... (1) y=2x-3 ... (2) 把(2)代入(1), x + 3(2x-3) = 1 x + 6x - 9 = 1 7x -9 = 1 7x = 10 x = 10/7 y = 2(10/7) - 3 = -1/7
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其他解答:1.y=2(1-3y)-3 y= 2-6y-3 7y=-1 y=-1/7 2.x+3y=1 ...(1) y=2x-3...(2) Put ' y=2x-3 ' into (1) x+3(2x-3)=1 7x-9=1 x=10/7 Put 'x=10/7' into (2) y=2(10/7)-3 y=20/14-3 y=-1/7|||||y=2(1-3y)-3 y=2-6y-3 y+3=2-6y 7y= -1 y= - 1/7 x+3y=1 ----1 y=2x-3 ----2 (2)----y=2x-3 -1/7=2x-3 -1/7 +3=2x 20/7 = 2x x = 40/7 SO: y= - 1/7 x = 40/7 唔知岩唔岩~太多年冇做
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