Question

Dam ''naj'' temu kto zrobi do 22
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Answer 1

A) y = x - 3
y = -½x + 3

y = x - 3
x - 3 = -½x + 3


y = x - 3
x + 0,5x = 3 + 3

y = x - 3
1,5x = 6/:1,5

y = x - 3
x = 4

y = 4 - 1
x = 4

y = 1
x = 4


b) x - y = 2
x + 2y = 5

x = 2 +y
2 + y + 2y = 5

x = 2 +y
3y = 5 - 2

x = 2 +y
3y = 3/:3

x = 2 +y
y = 1

x = 2 +1
y = 1

x = 3
y = 1

c)
y = -2x + 6
3x - 2y = 6

y = -2x + 6
3x - 2(-2x + 6) = 6

y = -2x + 6
3x +4x - 12 = 6

y = -2x + 6
7x = 6 + 12

y = -2x + 6
7x = 18/:7

y = -2x + 6
x = 18/7

y = -2 * 18/7 + 6
x = 18/7

y = 36/7 + 6
x = 18/7

y = 5 1/7 + 6
x = 18/7

y = 11 1/7
x = 18/7

d) -2x + y - 6 = 0
-x + y - 3 = 0

y = 0 + 6 + 2x
-x + 0 + 6 + 2x - 3 = 0

y = 6 + 2x
x + 3 = 0

x = 0 -3
y = 6 + 2x

x = -3
y = 6 + 2*(-3)

x = -3
y = 6 -6

x = -3
y = 0


e) -2x + y + 4 = 0
2x + y - 8 = 0

y = 0 -4 + 2x
2x + 0 -4 + 2x - 8 = 0

y = -4 + 2x
4x - 12 = 0

y = -4 + 2x
4x = 12/:4

y = -4 + 2x
x = 3

y = -4 + 2*3
x = 3

y = -4 + 6
x = 3

y = 2
x = 3


f) x + 2y + 1 = 0
3x - y + 3 = 0

x = 0 - 1 - 2y
3(0 - 1 - 2y) - y + 3 = 0

x = -1 - 2y
0 - 3 - 6y - y + 3 = 0

x = -1 - 2y
-7y = 0/:7

x = -1 - 2y
y = 0

x = -1 - 2*0
y = 0

x = -1 - 0
y = 0

x = -1
y = 0