Need help with these show work pls

3. 35 adults and 420 children

4. The three numbers are 13, 52 and 16

Step-by-step explanation:

3. Let the number of adults be x.

Since there are 12 times more children than adults,

number of children= 12x

Total number of people= 12x +x

13x= 455

x= 455 ÷13

x= 35

12x= 35(12)

12x= 420

Therefore, there are 35 adults and 420 children at the play.

4. Let the first number be x.

Since the 2nd number is 4 times the first,

2nd number= 4x

Third number is 3 more than the first:

3rd number= x+3

sum of numbers= x +4x +x+3

6x +3= 81 (simplify)

6x= 81 -3 (bring constant to 1 side)

6x= 78 (simplify)

x= 78 ÷6

x= 13

Second number

= 4x

= 4(13) (subst. x=13)

= 52 (expand)

third number

= x +3

= 13 +3 (subst. x=13)

= 16

(5x-1)^2= (5x)^2-2(5x)×1+(1)^2=25x^2-10x+1