Answer:
1- 1/3 x +3y=1
y=2/3 x-4
solution : x=39/7 , y=-2/7
3x-2y=11
-3x-y=4 solution x=1/3, y=-5
Step-by-step explanation:
1/3 x +3y=1
y=2/3 x-4
solve by substitution for y in the first equation:
1/3 x + 3(2/3 x-4)=1
1/3 x+6/3 x-12=1
7/3 x=12+1
7/3 x=13 ⇒7x=39 ⇒x=39/7=5 4/7
y=2/3 x -4
y=2/3 (39/7)-4
y=72/21 -4
y=-4/7
second problem:
3x-2y=11
-3x-y=4 solve by elimination: add two equation to eliminate x
3x-2y-3x-y=11+4
-3y=15
y=15/-3 ⇒y=-5
substitute y in one of the equations: 3x-2y=11
3x-2(-5)=11
3x+10=11
3x=11-10
x=1/3
