Question

I need this answers by using substitution method

Answer 1

Heya !!!
1) 2x-y-45 =0---------(i)
x-2y+21 = 0-------(ii)
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From equation (i)
2x -y = 45
x = 45+y/2-----(iii)
Putting x= 45+y/2 in equation (ii)
x-2y = -21
45+y/2-2y= -21
45+y - 4y = -42
45 - 3y = -42
-3y = -87
y = 29
Putting y = 29 in equation (iii)
x = 45+y/2
x = 45+29/2
x = 74/2
x = 37...
So,x = 37&y = 29
☆☆☆
2)2x+y-6=0
2x +y = 6--------(i)
4x-2y-4 =0
4x -2y = 4--------(ii)
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From equation (i)
2x+ y =6
x = 6-y/2-----(iii)
Putting x = 6-y /2 in eq.(ii)
4x-2y = 4
4( 6-y/2)-2y = 4
24 -4y-4y = 8
24 -8y = 8
- 8y = 8-24
-8y = -16
y = 2
Putting y = 2 in eq.(iii)
x = 6-y/2
x = 4/2
x = 2...
So ,x = 2 & y = 2...
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3) x +39y = 195-------(i)
11x +45y = 2325-------(ii)
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From equation (i)
x+39y = 195
x= 195 -39y
Putting x = 195-39y in eq.(ii)
11x +45y= 2325
11(195 -39y ) +45y = 2325
2145 -429y +45y = 2325
-384y = 180
y = -15/32
Putting y = -15/32 in equation (iii)
x = 195 - 39y
x = 195 - 39×(-15/32)
x = 195 +585/32
x = 6825/32..
x = 213.281..(approx)
☆☆☆
4)2x +y = 6------(i)
2x - y = -2----(ii)
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From equation (i)
2x +y =6
x = 6-y/2-------(iii)
Putting the value of x in eq.(ii)
2x -y = -2
2(6-y/2) -y = -2
12 -2y -2y = -4
12 -4y = -415
-4y = -16
y = 4...
Putting y = 4 in eq.(iii)
x= 6-y /2
x= 6-4/2
x = 2/2
x = 1
So,x = 1&y = 4
☆☆☆
5) 15u +22v = 5------(i)
40u+55v =13------(ii)
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From equation (i)
15u+22v = 5
u = 5-22v /15-------(iii)
Putting the value of u in eq.(ii)
40u + 55v = 13
40(5-22v/15)+55v = 13
200-880v +825v =195
-55v = 195 -200
-55v = -5
v = 5/55
v = 1/11
Putting v = 1/11 in eq.(iii)
u = 5-22v /15
u = 5- 2/15
u = 3/15
u = 1/5...
So , u = 1/5 & v = 1/11
THANKS
HOPE IT HELPS U☆☆☆☆