What is the sum of all roots of the equation
|x + 4|^2 - 10|x + 4| = 24?
Please help me find my mistake:
Let x+4=y
Now we get two cases,
Case1:
y^2-10y-24=0
Solving we get -2,12
Case2:
-y^2+10y-24=0
where we get 6,4
sum of all roots of the equation
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i think this eqn should be y^2+10y-24=0uptowngirl92 wrote:What is the sum of all roots of the equation
|x + 4|^2 - 10|x + 4| = 24?
Please help me find my mistake:
Let x+4=y
Now we get two cases,
Case1:
y^2-10y-24=0
Solving we get -2,12
it should be -12,2
Case2:
-y^2+10y-24=0
where we get 6,4
and roots =12,-2
and now putting back the values in the eqn
x+4=y
when y=-12;x=-16
y=2;x=-2
y=12;x=8
y=-2;x=-6
adding summ of the roots is -16
wats the OA
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Mind the Co-efficient of the square term in a quadratic equation.uptowngirl92 wrote:What is the sum of all roots of the equation
|x + 4|^2 - 10|x + 4| = 24?
Please help me find my mistake:
Let x+4=y
Now we get two cases,
Case1:
y^2-10y-24=0
Solving we get -2,12
Case2:
-y^2+10y-24=0
where we get 6,4
Example:
ax^2 -bx + c = 0
Here 'a' is the co-efficient of the square term.
Sum of roots is always b/a ( its not b)
Product of roots is always c/a ( its not c )
So if you multiple your case 1 with -1 you get case 2. But in your case 2 , signs of a,b and c are opposite of the same in case 1 and they cancel out.
So they are the SAME cases.
In the above light, you are solving the case 2 incorrectly because you ignored the fact that a = -1 and not 1.
You solved the case 1 correclty.