a) x= 5, 5^2= 5×5= 25
b) x= 2, 2×2^2= 2×(2×2)= 2×4= 8
c) x= 10, 2×10^2+1= 2×(10×10)+1= 2×100+1= 200+1= 201
d) x= 3, 3^2+3= (3×3)+3= 9+3= 12
