Solve the following ODEs by making an appropriate change of variable: dy 1-3y-9r (b) = dr 1+ y + 3x dy (a) (v² − z²¹) = - -2xy,

If possible, write -1- 12x - 8x² as a linear combination of -x-x², 2x + x² and 2x1 + x². Otherwise, enter DNE in all answer blanks. (-x-x²)+ -1-12x8x² (2x − 1 + x²). = (2x + x²)+

f. x² + 5x - 15 x - 2

Put the equation y = x² + 22x + 117 into the form y = (x – h)' + k: Answer: y = (x – (-11))² + (-4)