1.which of the following is the sum of the solutions of 4x^2-35x-9=0?
(F)-8
(G)8
(H)8.75
(J)9.25
solve this question by factoring
1. w^2-8w=0
please answer as soon as possible cos i have to hand this hw to my teacher tomorrow!!!
new york me44 math problems
2011-09-20 6:46 pm
回答 (2)
2011-09-23 6:05 am
✔ 最佳答案
1.Factorize 4x^2-35x-9 first.Let 4x^2-35x-9 be (4x+a)(x+b).
Then, split -9 into two numbers which only can be 1,9 or 3,3.(ignore negative signs first)
Let us try1,9 first.
The answer will be(4x+1)(x-9).
Either 4x+1 or x+9 equals to 0.
If 4x+1=0, x equals to -1/4.
If x-9=0, x equals to 9.
9+(-1/4)=8 3/4.
2.w^2-8w=0
Take away the common factor, it becomes to w(w-8)=0
so either w=0 or w-8=0
If w=0, w=0.
If w-8=0,w=8
So,w can be 0 or 8.
2011-09-20 7:26 pm
4x^2-35x-9=0
(4x+1)(x-9)=0
x = -1/4 (-0.25) or x = 9
their sum is : -0.25 + 9 = 8.75
+++
w^2 - 8w = 0
w(w - 8) = 0
w = 0 or w = 8
(4x+1)(x-9)=0
x = -1/4 (-0.25) or x = 9
their sum is : -0.25 + 9 = 8.75
+++
w^2 - 8w = 0
w(w - 8) = 0
w = 0 or w = 8
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