Răspuns:
Explicație pas cu pas:
x + 2y = 17
y - 3z = 4
a)
x + 3y - 3z = ?
x + 2y + y - 3z = 17 + 4
x + 3y - 3z = 21
___________
b)
2x + 5y - 3z = ?
2(x + 2y) + y - 3z = 2*17 + 4
2x + 4y + y - 3z = 34 + 4
2x + 5y - 3z = 38
___________
c)
(3x + 6y) + (2y - 6z) = ?
3(x + 2y) + 2(y - 3z) = 3*17 + 2*4 = 51 + 8 = 59
____________
d)
(2x + 4y)(x + 4y - 6z) = ?
2x + 4y = 2(x + 2y) = 2*17 = 34
x + 4y - 6z = x + 2y + 2y - 6z = x + 2y + 2(y - 3z) = 17 + 2*4 = 17 + 8 = 25
(2x + 4y)(x + 4y - 6z) = 34*25 = 850
