The points (4, 2) and (-1,y) are √74 units apart. What is the value of y?

Question

I know you should use the distance formula but I am unsure what to do next.

Answer 1

(4,2) and (-1,y)

 

√((4-[-1])²+(2-y)²)=√74

√(25+(2-y)²)=√74

square both sides

25+(2-y)²=74

25+4-4y+y²=74

y²-4y+29-74=0

y²-4y-45=0

factor

(y-9)(y+5)=0

y-9=0

y=9 answer