Answer:
(- 2, - 4 ) and (3, 10 )
Step-by-step explanation:
(2)
Given the 2 equations
4x - 7y = 20 → (1)
x - 3y = 10 → (2)
Rearrange (2) expressing x in terms of y, that is
x = 10 + 3y → (3)
Substitute x = 10 + 3y into (1)
4(10 + 3y) - 7y = 20 ← distribute and simplify left side
40 + 12y - 7y = 20
40 + 5y = 20 ( subtract 40 from both sides )
5y = - 20 ( divide both sides by 5 )
y = - 4
Substitute y = - 4 into (3) for corresponding value of x
x = 10 + 3(- 4) = 10 - 12 = - 2
Solution is (- 2, - 4 )
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(3)
3x + y = 19 → (1)
4x - y = 2 → (2)
Adding the 2 equations term by term will eliminate the y- term
(4x + 3x) + (- y + y) = 19 + 2, that is
7x = 21 ( divide both sides by 7 )
x = 3
Substitute x = 3 into either of the 2 equations and solve for y
Substituting into (1)
3(3) + y = 19
9 + y = 19 ( subtract 9 from both sides )
y = 10
Solution is (3, 10 )
