4(9x-1)=9 x(4-x) solve equation?
回答 (9)
✔ 最佳答案
4(9x-1)=9x(4-x)
36x-4=36x-9x^2
-4=-9x^2
(4/9)=x^2
x=sqr(4/9)
x=+ and - (2/3)
a^2 - b^2 â¡ (a + b)(a - b)
4(9x - 1) = 9x(4 - x)
4(9x) - 4(1) = 9x(4) - 9x(x)
36x - 4 = 36x - 9x^2
9x^2 + 36x - 36x - 4 = 0
9x^2 - 4 = 0
(3x)^2 - 2^2 = 0
(3x + 2)(3x - 2) = 0
3x + 2 = 0
3x = -2
x = -2/3
3x - 2 = 0
3x = 2
x = 2/3
ⴠx = ±2/3
4 (9x - 1) = 9x (4 - x)
First thing you have to do is distribute what's in the parenthesis.
4 * 9x + 4 * -1 = 9x * 4 + 9x * -x
36x - 4 = 36x - 9x²
Now, let's get x alone. But first, subtract 36x from both sides.
-4 = -9x²
Which is the same thing as:
4 = 9x²
by multiply or dividing each side by -1. I'm going to rearrange this so that x is on the left side rather than the right side, because I find it easier that way (personal preference, it doesn't really matter whether or not you do).
9x² = 4
Now, let's get x alone. 9 and x² are linked together by multiplication (9x² = 9 * x²), so let's do the inverse of multiplication to get x² alone.
Divide both sides by 9.
x² = 4/9
Now, since x is squared, we have to square root both sides. So,
(root)x² = (root)4/9
x = +or- 2/3
If you plug either of those two answers back into the original equation, they work. So we can assume that
x = 2/3 and - 2/3.
hope i helped :)
36x-4=36x-9x^2
9x^2-4=0
(3x-2)(3x+2)=0
x=2/3 & x=-2/3
4(9x-1) = 9 * x(4-x)
36x - 4 = 36x - 9x^2
9x^2 = 4
x^2 = 4/9
x = +- sqrt(4/9)
x = -2/3, 2/3
:D
4(9x-1)=9x(4-x)
.......36x-1=36x-x^2
.......x^2-1=0
.......X^2=1
.......x=1,-1
36X-4=36X-9X^2
THEREFORE 9X^2=4
X^2=4/9
X=2/3
收錄日期: 2021-05-01 12:39:58
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