Devaughn's age is three times sydney's age. the sum of their ages is 80. what is sydney's age?

According to modern science, earth is about 4.5 billion years old and written human history extends back about 10,000 years. suppose the entire history of earth is represented with a 10-meter-long timeline, with the birth of earth on one end and today at the other end.

How many solutions does the nonlinear system of equations graphed below have?

Can some one explain this i got sent this. is this a threat i’m scared