Question

А)2x+y=11     5x-4y=8 б) 2x+y=-2     -x+4y=19 в) 2x-3y=8     7x-5y=-5

Answer 1

1)2x+y=11/*4⇒8x+4y=44
5x-4y=8
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13x=52
x=52/13=4
8+y=11
y=11-8=3
(4;3)
2)2x+y=-2
-x+4y=19/*2⇒-2x+8y=38
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9y=36
y=36*9=4
-x+16=19
x=16-19=-3
(-3;4)
3)2x-3y=8/*7⇒14x-21y=56
7x-5y=-5/-2⇒-14x+10y=10
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-11y=66
y=-6
2x+18=8
2x=8-18=-10
x=-10/2=-5
(-5;-6)