11x^2 + 7(9x - x^2) + 15x = 4x^2 + 78x?

Question

How do I check to see if the first equation equals the second equation?


I distribute the 11x^2 to the 9x and -x^2 ?

And distribute the 7 to the 9x and -x^2 ?

Maybe someone can help me

Thanks

Answer 1

Where is the second equation? I see only one.
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11 x^2 + 7 (9x - x^2) + 15 x = 4 x^2 + 78 x
=>
11 x^2 + 63 x - 7 x^2 + 15 x = 4 x^2 + 78x

BTW this equation is an identity. (= Is always valid for any x.)
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Answer 2

11x^2 + 7(9x - x^2) + 15x = 4x^2 + 78x

11x^2 + 63x - 7x^2 + 15x = 4x^2 + 78x expand the brackets

11x^2 - 7x^2 - 4x^2 = 78x - 63x - 15x group like terms

looks as if x = 0 and if u were to put x=0 in both sides of the eqn they will both be 0

Answer 3

Okie Dokie, you first distribute the parentheses,

7(9x-x^2) = 63x-7x^2.

And then you simplify the like equations, (eg. x^2 with x^2, x with x).
Thus You simplify the

(11x^2 - 7x^2 - 4x^2)+(63x+15x-78x)=0

and thus 0=0. Ya digg?

Answer 4

My simplification comes out to this:

11x^2 + 63x -7x^2 + 15x = 4x^2 + 78x

4x^2 + 63x + 15x = 4x^2 + 78x

63x + 15x = 78x

78x = 78x

So, yes, the first equation equals the second one.