You can
put this solution on YOUR website!Question:
Please help me, I can not get this to factor- 7x^2+34x-5
Answer:
Here you can use the method of splitting middle term..
For that you have to find out two numbers so that their sum is +34(that is coefficient of x ) and whose product is -35( that is 7 * -5)
Such two numbers are +35 and -1
Now split the middle term using these two numbers.
==>
Now group the terms as follows...
==>
Now take out the common terms form each group....
==>
Now (1x + 5) is common in both groups, so take it outside.
===> (1x + 5 ) ( 7x + 5 ) = 0,
So the factors of the given equation is
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If you want to solve this equation.....
(1x + 5 ) ( 7x + 5 ) = 0
==> either (1x + 5 ) = 0 or ( 7x + 5 ) = 0
(1x + 5 )= 0 ==>
and
( 7x + 5 ) = 0 ==> 7x = -5 ==>
Hope you found the explanation useful.
Regards.
Praseena
You can
put this solution on YOUR website!factor-
7x^2 + 34x - 5
:
You can see that 7 only has 1 & 7 as factors
Also 5 has only 5 and 1 as factors
:
You know it will be this because the middle term is 34 (7*5):
(7x__ 1)(x___5)
:
Now just find the signs that will make this thing work
(7x - 1)(x + 5)
:
Check it by FOILing these factors; 7x^2 + 35x - 1x - 5 = 7x^2 + 34x -5
:
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You can
put this solution on YOUR website!7x^2+34x-5
Here we apply quadratic formula
x= -b+or- sqrt of b^2 -4ac/2a
here a = 7 , b= 34 , c= -5
==> -34 +/- sqrt of (34)^2-( 4*7*-5)/2*7
==> -34 +/- sqrt of 1156+140/14
==> -34+/- sqrt of 1296/14
==> -34 +/- 36/14
==> 2( -17 +/- 18)/2*7 ( 2 is taken as common factor)
==>-17 +/- 18 /7 ( 2 in the numerator and denominator gets cancelled)
x = -17 + 18/ 7 and -17 -18/7
x = 1/7 and x = -35/7 = -5
Hence the solution for x= 1/7 and -5
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