Ineed with number 4 pleaaasssee or if you can just explain so i can understand that would alot

a=3

a= -19

Step-by-step explanation:

(a+7i)  (-8+4i)   distance = sqrt(130)

distance = sqrt( (x2-x1) ^2 + (y2-y1) ^2)

fill in what we know

sqrt(130) =sqrt( (-8-a) ^2 + (4-7) ^2))

square each side

(130) =( (-8-a) ^2 + (4-7) ^2))

130 = (-8-a) ^2 + (-3) ^2)

130 =  (-8-a) ^2 + 9

subtract 9 from each side

130 -9 =  (-8-a) ^2 +9-9

121=  (-8-a) ^2

take the square root of each side

sqrt(121) = sqrt( -8-a)^2)

remember to take the plus and minus when taking the square root

±11 =( -8-a)

11 = -8-a    or -11 = -8-a

add 8 to each side

8+11 = 8-8-a    or  8-11 = 8-8-a

19 = -a      or        -3 = -a

multiply by -1

a = -19         or  a = 3