Answer:
(- 1, 5 )
Step-by-step explanation:
Using the method of substitution.
Given the 2 equations
3x + 2y = 7 → (1)
x - 4y = - 21 → (2)
Rearrange (2) expressing x in terms of y by adding 4y to both sides.
x = 4y - 21 → (3)
Substitute x = 4y - 21 into (1)
3(4y - 21) + 2y = 7 ← distribute and simplify left side
12y - 63 + 2y = 7
14y - 63 = 7 ( add 63 to both sides )
14y = 70 ( divide both sides by 14 )
y = 5
Substitute y = 5 into (3)
x = (4 × 5) - 21 = 20 - 21 = - 1
Solution is (- 1, 5 )
Answer:
500
Step-by-step explanation:
You solve the substitution method to solve a system of equality by expressing one variable in terms of the other using one equation, and then plugging this expression in the other(s).
In this case, the first equation gives us a way to express n in terms of m. So, we can replace every occurrence of n in the second equation with the given formula.
The result is
So, the second equation turned to be an equality, i.e. an equation where both sides are the same.
This implies that the system has infinitely many solutions, because every couple 
such that 
is a solution to the system, because it satisfies both equations: the first is trivially satisfied, whereas the second is an identity, and as such is satisfied by any value of the variable.
Answer:
Step-by-step explanation:
its A)
