/* Zadanie 1 */

r1: y^2 - 8*y + 15 = 0;
solve(r1);

/* Zadanie 2 */

r1: 2*x + 3*y = 8;
r2: x + 2*z = 2;
r3: y + 4*z = 4;
solve([r1, r2, r3], [x, y, z]);