Step-by-step explanation:
a .
x + y = 6
+
2x - y = 3
3x = 9
3x/3 = 9/3
x = 3
x + y = 6
y = 6 -x
y = 6 - 3
y = 3
b.
2x - y = 7
+
y = 3x
2x = 3x + 7
2x - 3x = 7
x = -7
y = 3x
y = 3(-7)
y = -21
c.
[tex] {x}^{2} + \frac{1}{16} = \frac{x}{2} [/tex]
[tex] {x}^{2} + \frac{1}{16} - \frac{x}{2} = 0[/tex]
[tex]16( {x}^{2} - \frac{x}{2} + \frac{1}{16} ) = 0[/tex]
[tex]16 {x}^{2} - 8x + 1 = 0[/tex]
[tex](4x - 1)(4x - 1) = 0[/tex]
[tex]x = \frac{1}{4} [/tex]
2.
a.
[tex] {a}^{2} - 2a - 2b - {b}^{2} [/tex]
[tex]a(a - 2) - b(b + 2)[/tex]
