Answer:
The second: 0≤x≤20 , -10≤y≤20
Step-by-step explanation:
for x = 0 it is:
y = -0+9 = 9 {y at scope in the first, second and fourth but not the third}
and y = 0.5•0 - 6 = -6 {y at scope in all but the first}
for x = 20:
y = -20+9 = -11 {y almost at scope in the second but not in the first}
and y = 0.5•20 - 6 = 4 {y at scope in both, the first and the second}
for x = -20:
y=-(-20)+9 = 29 {y out of scope in both, the third and the fourth}
and y = 0.5•(-20)-6 = -16 {y out of scope in both}
