Let a(x) be the amount of money remaining on Hillary's gift card after purchasing x apps on her phone. a(x) = 50 - 1.25x Since a(12) ___= , Hillary will have dollars remaining on her card after purchasing ___ apps.

step-by-step explanation:

the answer is 13

step-by-step explanation:

5*5=25

12*12=144

25+144=169

169^2=13

substitute,

circle 1 = 5

circle 2 = 20

circle 3 = 44

in this case no matter how you add, you will always get a perfect square..

hence proved

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