Solve using the quadratic formula:x^2 – 2x = 15x – 10?
回答 (8)
✔ 最佳答案
x²-17x+10=0
x=17±√-17²-4(1)(10)/2
x=17±√289-40/2
x=17±√249/2
x² - 2x = 15x - 10
x² - 17x = - 10
x² - 17/2x = - 10 + (- 17/2)²
x² - 17/2x = - 40/4 + 289/4
(x - 17/2)² = 249/4
x - 17/2 = 7.889867
x = 7.889867 + 8.5, x = 16.389867
x = - 7.889867+ 8.5, x = 0.610133
Answer: x = 16.389867, 0.610133
Proof (x = 14.464179):
16.389867² - 2(16.389867) = 15(16.389867) - 10
268.628 - 32.78 = 245.848 - 10
235.848 = 235.848
Proof (x = 0.610133):
0.610133² - 2(0.610133) = 15(0.610133) - 10
0.372 - 1.22 = 9.152 - 10
- 0.848 = - 0.848
x^2-2x=15x-10
x^2-17x+10=0
a=1 b=-17 c=10
-(-17)+/- sqrt -17^2-4(1)(10)/2
17+/- sqrt 289-40/2
17+/- sqrt 249/2
x^2 - 2x = 15x - 10
x^2 - 2x - 15x + 10 = 0
x^2 - 17x + 10 = 0
x = [-b 屉(b^2 - 4ac)]/2a
a = 1
b = -17
c = 10
x = [17 屉(289 - 40)]/2
x = [17 屉249]/2
â´ x = [17 ±â249]/2
x² - 2x = 15x - 10
â subtract 15x from both sides â
x² - 17x = -10
â add 10 to both sides â
x² - 17x + 10 = 0
â plug into the quadratic formula â
[-(-17) ± â((-17)² - 4(1)(10))] / 2(1)
â Simplify down to â
(17/2) ± (1/2)â249
â write as roots â
x = (17/2) - (1/2)â249 â 0.6101
x = (17/2) + (1/2)â249 â 16.3899
x^2 - 2x = 15x - 10
x^2 - 17x + 10 = 0
x = [ -b +/- sqrt(b^2 - 4ac) ] / [ 2a ]
x = [ 17 +/- sqrt( (-17)^2 - 4(1)(10) ) ] / [ 2(1) ]
x = [ 17 +/- sqrt( 289 - 40 ) ] / [ 2 ]
x = [ 17 +/- sqrt(249) ] / 2
x^2 - 17x + 10 = 0
x = (17+sqrt249)/2, (17-sqrt249)/2
x ² - 17 x + 10 = 0
x = [ 17 ± â (289 - 40 ) ] / 2
x = [ 17 ± â (249) ] / 2
收錄日期: 2021-05-01 11:42:16
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