-124+34-12-89+(18-37)
489-833-29+93-489-93+862
-192-189+83+92-(238+(-83+89))
239*(71-91)+(783-83*(293+893)+83)+102352
(3738-388)+8229-(388-(289-(188+(3838-828))))
x^2-10x+21=0
x^2+6x+5=0
x^2-6x-20=0
x^2-x+1=0
x^2-4x-12=0