5x +2(x+20)+10+5x+20+3(x+10)=770. solve for x

Step-by-step explanation:

calculate those with x values

15x + 100 = 770

...then collect like terms

15x = 770-100

and divide both sides by 15

x = 670

15.

x = 44⅔

third option: 6x+8

step-by-step explanation:

we can see that the given question is a sum of series and the values of n vary from 0 to 3

the first term will be:

when n=0, [(0)*x+2] => (0+2) => 2

when n=1, [(1)*x+2] => (x+2) => x+2

when n=2, [(2)*x+2] => 2x+2

when n=4, [(3)*x+2] => 3x+2

so adding up all the terms will give us:

=2+x+2+2x+2+3x+2

=x+2x+3x+2+2+2+2

=6x+8

so,

third option is the correct answer ..