Πεψενθε 

`implies`(`implies`(`*`(9, 7) = `+`(`+`(`*`(`^`(a, 2)), `+`(`*`(4, `*`(`^`(a, 2))))), `*`(`/`(1, 2), `*`(`*`(`+`(`*`(2, `*`(a))), 2), `*`(a)))), 63 = `+`(`*`(7, `*`(`^`(a, 2))))), a = 3)