9z^2-30z=-25
2007-09-30 17:44:32 · 8 answers · asked by MTak 2 in Science & Mathematics ➔ Mathematics
9z² - 30z + 25 = 0
(3z - 5)(3z - 5) = 0
z = 5/3
2007-09-30 19:43:45 · answer #1 · answered by Como 7 · 0⤊ 0⤋
This type of question would normally have 2 answers, so don't listen to people giving you a hard time about that, they clearly are the stupid ones!
Rearrange the equation to:
9z² - 30z +25 = 0
and then sub into the quadratic equation:
z = (- b ± sqrt(b² - 4ac)) / 2a
where a = 9, b = -30 and c = 25.
you will end up with:
z = (30 ± 0) / 18
ie. z = 30/18
which is z = 5/3
In this case, it's only because b² = 4ac that there is only one answer, ie you've found the turning point of your curve.
2007-10-01 01:00:43 · answer #2 · answered by Buffy S 3 · 0⤊ 0⤋
9z^2-30z=-25
so 9x^2 - 30z +25 = 0
so (3x-5)^2 = 0
so x = 5/3
.
2007-10-01 00:46:58 · answer #3 · answered by tsr21 6 · 0⤊ 0⤋
9z^2 - 30z = -25
9z^2 - 30z + 25 = 0
That's a quadratic equation which can be represented as
(3z-5)^2 = 0
(3z-5) x (3z-5) = 0
3z-5 = 0/(3z-5)
3z-5 = 0
3z = 5
z- 5/3
2007-10-01 01:16:22 · answer #4 · answered by Anonymous · 0⤊ 0⤋
9z² - 30z = -25
9z² - 30z + 25 = 0
9z² - 15z - 15z + 25 = 0
3z(3z - 5) - 5(3z - 5) = 0
(3z-5)(3z-5) = 0
(3z-5)² = 0
z = 5/3
2007-10-01 00:47:45 · answer #5 · answered by gudspeling 7 · 0⤊ 0⤋
use the quadratic formula
you may end up w/ negative or positive answer; try it
2007-10-01 00:51:18 · answer #6 · answered by ramel pogi 3 · 0⤊ 0⤋
if this equation have more than 1 answer , you'll not pass any math test - i swear ^_^
2007-10-01 00:49:50 · answer #7 · answered by Finnergan Ho 2 · 0⤊ 0⤋
18z=-5
2007-10-01 00:47:19 · answer #8 · answered by Ricardus 4 · 0⤊ 0⤋