Answer:
Question 2: No Solution
Question 4: (2,-3)
Explanation:
Question 2: {x-y=7} {x-y=-4}
Question 4: {5x+2y=4} {9x+2y=12}
There is two ways of solving this;
Elimination method and Substitution method.
I will be using the Substitution method for Question 2 and Elimination method for Question 4.
Substitution method is basically substituting in the equation like this;
Question 2:
x - y = 7 and x - y = -4
x - y = 7 into x = 7 + y
Substitute:
7 + y - y = - 4
7 = - 4
7 ≠ - 4
Therefore, there no solution to this equations.
Question 2: No Solution
Question 4:
Elimination Method is basically eliminates one of the variables, so we can solve a more simplified equation.
5x + 2y = 4 and 9x + 2y =12
5x + 2y = 4
-(9x + 2y = 12) - Multiply this equation by -1.
Now we have;
5x + 2y = 4
-9x -2y = -12
-4x = -8
x = 2
We can substitute x to find y.
5(2) + 2y = 4
10 + 2y = 4
2y = -6
y = -3
(2,-3)
Question 4 Solution: (2,-3)
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