Please help me this is called Writing Equations

Which expression is equivalent to 2x^2+2x-4/2x^2-4x+2

You paid 28.00 for 8 gallons of gasoline. how much would you pay for 15 gallons of gasoline?

17. a researcher measures three variables, x, y, and z for each individual in a sample of n = 20. the pearson correlations for this sample are rxy = 0.6, rxz = 0.4, and ryz = 0.7. a. find the partial correlation between x and y, holding z constant. b. find the partial correlation between x and z, holding y constant. (hint: simply switch the labels for the variables y and z to correspond with the labels in the equation.) gravetter, frederick j. statistics for the behavioral sciences (p. 526). cengage learning. kindle edition.