I have real problems trying to figure this out, as I was not in class when er learned this. Does anyone know how to??
Ok so here is the question:
21d*d+8d-26= 0
What are the steps that you have to take???
Thank you so much for helping me
seetbinti
I have real problems trying to figure this out, as I was not in class when er learned this. Does anyone know how to??
Ok so here is the question:
21d*d+8d-26= 0
What are the steps that you have to take???
Thank you so much for helping me
seetbinti
$\displaystyle 21d^2 + 8d - 26 = 0$
The quickest approach is the quadratic formula.
-Dan
$\displaystyle 21d*d+8d-26= 0 is also written as
21d^2+8d-26= 0$
now you can factorize this equation or as the above guy said use the quadratic formula, but assuming you don't know it I'll show you the factorizing method !!!
so , $\displaystyle 21d^2 + 8d - 26 = 0$
we can't split middle term so we do it by completing the square or by converting it to the form (a+b)^2 = 0
so, we first transpose -26 to the RHS
so we get
$\displaystyle 21d^2 + 8d = 26$
we no divide the whole equation by 21 to x^2 coefficient to a perfect square and 1 is a perfect square.
so we get
$\displaystyle d^2 + 8/21d = 26/21$
can be written as
$\displaystyle d^2 + 2(1)(4/21) = 26/21$
no we add (4/21)^2 to both sides just to make the whole expression (a^2 + 2ab + b^2)ish
so,
$\displaystyle d^2 + 2+(1)(4/21) + (4/21)^2 = 26/21 + (4/21)^2$
factorizing LHS we get
$\displaystyle (d+4/21)^2 = 26/21 + 16/441$
$\displaystyle (d+4/21)^2 = (546 + 16)/441$
$\displaystyle (d+4/21)^2 = 562/441
$
$\displaystyle d+4/21$ = PLUS OR MINUS $\displaystyle Sqrt(562)/21$
$\displaystyle d$ = PLUS OR MINUS$\displaystyle Sqrt(562)/21 - 4/21$
and thats the solution.
Ice Sync