Is these algebraic expression correct

  • #1
1.(x - 3)2 = 4
x2 - 6x + 5 = 0
(x - 1)(x - 5) = 0
x = -1, -5
(is this correct)

2. 2x + 4 / x +1 = x - 8 / 2x - 1
(2x + 4)(2x - 1) = (x - 8)(x + 1
4x2 - 2x + 8x - 4 = x2 - 7x -8
4x2 - 6x - 4 = x2 - 7x - 8
(where do i go from here)

3. (x / 3) - (y / 2) = -1
(y / 2) = -4 - 3x
6x + y = -8
y = -8 - 6x
(x / 3) - (-4 - 3x) = -1
(10 / 3) x + 4 = -1
x = -5 / (10 / 3) = (-3 / 2) x = -3 / 2
6(-3 / 2) + y = -8
y = -8 + 6(-3 / 2)
y = -8 + (-18 / 2)
y = (-144 +- 16 / 16) y = -10
(is this correct)
 

Answers and Replies

  • #2
Pengwuino
Gold Member
5,009
16
1. No, they should be positive. If you plugged in either x=-1 or x=-5, you'd see that product didn't equal 0.

2. For this question, is what you're asking [tex]\frac{{2x + 4}}{{x + 1}} = \frac{{x - 8}}{{2x - 1}}[/tex]? If so, it looks good. Now you simply want to subtract [tex]x^2 - 7x - 8[/tex] from both sides so you have 0 on the right side and a simple quadratic on the left.

3. This looks a little confusing. Can you put spaces between each set of equations so we know exactly what you're doing? If the third line is suppose to be manipulation of the first line, it doesn't look correct.
 

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