Answer:
(3, - 1)
Step-by-step explanation:
5x - 4y = -11
2x + 3y = -9
Multiply the top equation by 2 and the bottom equation by - 5 to cancel out the x's.
10x - 8y = - 22
- 10x - 15y = 45
Cancel out x's.
-8y = - 22
- 15y = 45
Add like terms.
- 23y = 23
Can't have a negative variable to flip them.
-23 = 23y
Divide.
y = - 1
Input y into one of the equations and solve for x.
2x + 3(-1) = -9
Simplify.
2x -3 = -9
Cancel out -3 by adding 3.
2x = -6
Divide.
x - -3
(not <em>a</em> or not <em>b</em>) implies <em>c</em> <==> not (not <em>a</em> or not <em>b</em>) or <em>c</em>
so negating gives
not [(not <em>a</em> or not <em>b</em>) implies <em>c</em>] <==> not[ not (not <em>a</em> or not <em>b</em>) or <em>c</em>]
which we can simplify somewhat to
not (not (not <em>a</em> or not <em>b</em>)) and not <em>c</em>
(not <em>a</em> or not <em>b</em>) and not <em>c</em>
(not <em>a</em> and not <em>c</em>) or (not <em>b</em> and not <em>c</em>)
not (<em>a</em> or <em>c</em>) or not (<em>b</em> or <em>c</em>)
not ((<em>a</em> or <em>c</em>) and (<em>b</em> or <em>c</em>))
not ((<em>a</em> and <em>b</em>) or <em>c</em>)
