[tex] \sqrt{ ({ - 1 - 7})^{2} + ({2 - a})^{2} } = \sqrt{ ({ - 1 - a})^{2} + ({2 - ( - 3)})^{2} } \\ [/tex]
Bring both sides of the equation to the power of 2
[tex]( { - 8})^{2} + ({2 - a})^{2} = ({ - 1 - a})^{2} + ({2 + 3})^{2} \\ [/tex]
[tex]64 + 4 - 4a + {a}^{2} = 1 + 2a + {a}^{2} + 25 \\ [/tex]
[tex] {a}^{2} - 4a + 68 = {a}^{2} + 2a + 26 [/tex]
Subtract sides -26
[tex] {a}^{2} - 4a + 68 - 26 = {a}^{2} + 2a + 26 - 26 \\ [/tex]
[tex] {a}^{2} - 4a + 42 = {a}^{2} + 2a [/tex]
Subtract sides -a²
[tex] {a }^{2} - {a}^{2} - 4a + 42 = {a}^{2} - {a}^{2} + 2a \\ [/tex]
[tex] - 4a + 42 = 2a[/tex]
Plus sides 4a
[tex]4a - 4a + 42 = 2a + 4a[/tex]
[tex]42 = 6a[/tex]
Divided sides by 6
[tex] \frac{42}{6} = \frac{6}{6}a \\ [/tex]
[tex]a = 7[/tex]
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And we're done.....♥️♥️♥️♥️♥️
