Question

80-[15x-7(6x-9)-21{10x+5(42-3x)}]​

Answer 1

Answer:

80-[15x-42x+63-21(10x+210-15x)]

=80-[-27x+63-210x-4410+315x]

=80+27x-63+210x+4410-315x

= - 78x+4427

x=73.538

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Answer 2

$f(x)=-78x+4427$

Step-by-step explanation:

Given,

$f\left ( x\right )=80-\left [ 15x-7\left ( 6x-9 \right )-21\left \{ 10x+\left5 ( 42-3x\right ) \right \} \right ]$

Solution,

$f\left ( x \right )=80-\left [ 15x-7\left ( 6x-9 \right )-21\left \{ 10x+\left5 ( 42-3x\right ) \right \} \right ]$

$=80-\left [ 15x-42x+63-21\left \{ 10x+210-15x \right \} \right ]$

$=80-\left [ -27x+63-210x-4410+315x \right ]$

$=80-\left [ 78x-4347 \right ]$

$=80-78x+4347$

$=-78x+4427$