Hey can someone please help me!!???

The equation x2 – 1x – 90 = 0 has solutions {a, b}. what is a + b?

(mc 02.03) what set of reflections and rotations would carry rectangle abcd onto itself? reflect over the y-axis, reflect over the x-axis, rotate 180° rotate 180°, reflect over the x-axis, reflect over the line y=x reflect over the x-axis, rotate 180°, reflect over the x-axis rotate 180, reflect over the y-axis, reflect over the line y=x

How many kilograms of a 5% salt solution and how many kilograms of a 15% salt solution must be mixed together to make 45kg of an 8% salt solution?