Answer and Step-by-step explanation: The distance between 2 points is the distance of the straight line that passes through both points. It calculated using the following formula:
d = [tex]\sqrt{(x_{B} - x_{A} )^{2} + (y_{B} - y_{A} )^{2} }[/tex]
1) For A (2,1) and B(4, -1)
d = [tex]\sqrt{(4-2)^{2} + (1+1)^{2} }[/tex]
d = [tex]\sqrt{4+4}[/tex]
d = 2[tex]\sqrt{2}[/tex]
2) 5 = [tex]\sqrt{(0-x)^{2} + (1-2)^{2} }[/tex]
25 = x² + 1
x² = 24
x = 2[tex]\sqrt{6}[/tex]
3) d = [tex]\sqrt{(-5-2)^{2} + (-2-5)^{2} }[/tex]
d = [tex]\sqrt{(-7)^{2} + (-7)^{2} }[/tex]
d = 7[tex]\sqrt{2}[/tex]