a) [tex]x^{2} + 2x \times 1 + 1^{2} = (x + 1) ^{2} [/tex]
[tex](x + 1) ^{2} = 169 \\ x + 1 = 13 \\ x = 12[/tex]
b)
[tex](2y)^{2} + 2 \times 2y + 1 ^{2} = (2y + 1) ^{2} [/tex]
[tex](2y + 1) ^{2} = 81 \\ 2y + 1 = 9 \\ 2y = 8 \\ y = 4[/tex]
c)
[tex]z ^{2} + 2 \times 3 \times z + 3 ^{2} = (z + 3) ^{2} [/tex]
[tex](z + 3) ^{2} = 5 \\ z + 3 = \sqrt{5} \\ z = \sqrt{5} - 3[/tex]
[tex](3t) ^{2} + 2 \times 3 \times 2 + 2^{2} = (3t + 2) ^{2} [/tex]
[tex](3t + 2) ^{2} = 25 \\ 3t + 2 = 5 \\ 3t = 3 \\ t = 1[/tex]
