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2x + y = 11 (Eq. 2)
You can solve such pair of simultaneous equations in two variables by three methods. Elimination, substitution and, if you like, graphical.
I will do the substitution approach here.
From equation 2, making y the subject,
y = 11 - 2x (Eq. 3)
Substituting Eq. 3 into Eq. 1,
3x - 4y = 33
3x - 4 (11 - 2x) = 33
3x - 44 + 8x = 33
11x = 77
x = 7
Substituting x = 7 into Eq. 3,
y = 11 - 2x
y = 11 - 2 (7)
y = -3
So, x = 7 and y = 3
[Check]
(Eq. 1)
3x - 4y
= 3 (7) - 4 (-3)
= 21 + 12
= 33
(Eq. 2)
2x + y
= 2 (7) + (-3)
= 14 - 3
= 11
See 1 Answer