8(-3)^2+7(3)^2= 8*9 + 7*9 =72+63=135
8a^2+7b^2,a=-3, b=3.
8*(-3)^2 + 7*3^2 =8*3^2 + 7*3^2=15*3^2= 15*9=135
8(-3)^2+7(3)^2= 8*9 + 7*9 =72+63=135
8a^2+7b^2,a=-3, b=3.
8*(-3)^2 + 7*3^2 =8*3^2 + 7*3^2=15*3^2= 15*9=135