1- After properly factoring the following equation, what would be the next appropriate written step in the process of solving for x?
2x^2 - 3x - 20 = 0
A - x - 4 = 0
B - 2x + 5 = 0 and x - 4 = 0
C - x + 4 = 0
D - 2x - 5 = 0 and x + 4 = 0
2- After properly factoring the following equation, what would be the next appropriate written step in the process of solving for x?
x^2 + 6x - 40 = 0
A - x - 10 = 0 and x + 4 = 0
B - x + 10 = 0 and x - 4 = 0
C - x + 10 = 0
D - x - 4 = 0
I really need HELP PLEEEEASE.
10 Points for Best Answer. Thank You
2006-08-25 14:48:16 · 8 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
1)
2x^2 - 3x - 20 = 0
Factored it is (x-4)(2x+5)=0
So its B
2)x^2 + 6x - 40 = 0
Factored it is (x-4)(x+10)=0
So its B
2006-08-25 14:56:28 · answer #1 · answered by Anonymous · 0⤊ 0⤋
1)
First, factor it yourself:
2x^2 - 3x - 20 = 0
(2x )(x ) = 0
(2x 5)(x 4) = 0
(2x + 5)(x - 4) = 0
Check:
2x(x - 4) + 5(x - 4) = 0
2x^2 - 8x + 5x - 20 = 0
2x^2 - 3x - 20 = 0
So, (2x + 5)(x - 4) = 0 is the correct factoring.
At this point, either factor can be equal to zero:
2x + 5 = 0 and x - 4 = 0
B
2) Same on this one:
x^2 + 6x - 40 = 0
(x )(x ) = 0
(x - 4 )(x + 10) = 0
Check: x(x + 10) - 4(x + 10) = 0
x^2 + 10x - 4x - 40
x^2 + 6x - 40 = 0 ----> it works
(x - 4 )(x + 10) = 0
x + 10 = 0 and x - 4 = 0
B
2006-08-25 22:13:42 · answer #2 · answered by Anonymous · 0⤊ 0⤋
After factoring 2x^2 -3x -20 =0 you get
(2x + 5)(x-4) = 0.
Now a product is zero if and only if at least one of
the factors is zero.
So one must set each factor to zero and solve, so
the next step is B. 2x + 5 = 0 and x -4 = 0.
The second question is done the same way:
What are the factors?
Now set each factor to zero and solve.
Again, the answer is B.
Hope that helps a bit.
2006-08-25 22:08:35 · answer #3 · answered by steiner1745 7 · 0⤊ 0⤋
The factors of the first equation are (x+4) and (2x-5). The equation is zero when either factor is zero. This means x+4 = 0 and 2x-5 =0, case B
The factors in your second equation are (x+10) and (x-4). Again, either factor must be zero, which is case B
2006-08-25 22:19:04 · answer #4 · answered by gp4rts 7 · 0⤊ 0⤋
x = -4
2006-08-26 05:52:53 · answer #5 · answered by Ed 1 · 0⤊ 0⤋
Both questions involve quadratics, so you know there will be two solutions for x. Which of the possible letter selections indicate two answers? Then, which ones, when multiplied together, give you the original equation?
You must try young grasshopper.
2006-08-25 22:25:29 · answer #6 · answered by SAN 5 · 0⤊ 0⤋
1. B
2. B
2006-08-25 21:57:37 · answer #7 · answered by gatorgrad99_99 3 · 0⤊ 0⤋
Way to help him cheat on his H/W!
2006-08-25 21:59:04 · answer #8 · answered by Quick2Answer 3 · 0⤊ 0⤋