4x2 - 5x + 9 = 0
How many solutions does this problem have please help

In the field of thermodynamics, rankine is the unit used to measure temperature. one can convert temperature from celsius into rankine using the formula , what is the temperature in celsius corresponding to r degrees rankine? a. 9/5(c - 273) b. 9/5(c + 273) c. 5/9( c - 273) d. 5/9( c + 273)

Need plz been trying to do it for a long time and still haven’t succeeded

Zahra wants the equation below to have an infinite number of solutions when the missing number is placed in the box.