Explain solving systems of equations using substition?

Find the roots of the equation below. x^2 - 6 + 9 = 0

Is the square root of 4 plus the square root of 16 rational?

According to the 2008 u. s. census, california had a population of approximately 4 × 10^7 people and florida had a population of approximately 2 × 10^7 people. which of the following is true? a. the population of california was approximately two times the population of florida. b. the population of florida was approximately twenty times the population of california. c. the population of florida was approximately two times the population of california. d. the population of california was approximately twenty times the population of florida.