Question

x+2y = 17
y-3z= 4
x+3y-3z=
2x+5y-3z=?
(3x+6y)+(2y-6Z)=?
(2x+4y)x(x+4y-z)=?

Answer 1

x + 3y - 3z = x + 2y + y - 3z = 17 + 4 = 21
2x + 5y -  3z = 2x + 4y + y - 3z = 2(x + 2y) + (y - 3z) = 2×17 + 4 = 34 + 4 = 38
(3x + 6y) + (2y -6z) = 3(x + 2y) + 2(y - 3z) = 3×17 + 2×4 = 51 + 8 = 59
(2x + 4y) × (x + 4y -z) = 2(x + 2y) × (x + 2y + 2y - z) = 2×17×(17 + 2y - z) =
= 34 × (17 + 2y - z) = 34 × ( 17 + 8 - 6z - z) = 34 × (25 - 7z)
y = 4 - 3z
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