Question

SOLVE THE FOLLOWING LINEAR EQUATIONS BY SUBSTITUTION METHOD:
(a). X-2Y=1
2X+Y=7
(b). X+2Y=5
2X-3Y= - 4
( c). 2X-Y=1
X+2Y=8
(d) X+3Y=15
2X-Y=2
(e) X+Y=6
2X-Y =0​

Answer 1

Answer:

a) X-2Y=1

X =1+2Y

2X+Y=7 - - - - - - - - - - - equation1

Substitute X in equation 1

2(1+2Y)+Y=7

2+4Y+Y=7

2+5Y=7

5Y=5

Y=1

X=1+2(1)

X=3

b) X=5-2Y

2X-3Y=-4 - - - - - - - - - equation 1

Substitute Xin equation 1

2(5-2Y)-3Y=-4

10-4Y-3Y=-4

10+4 =7Y

7Y=14

Y=2

X=5-4

X=1

c)2X-Y=1

2X-1 =Y

X+2Y=8- - - - - - - - equation1

X+2(2x-1)=8

X+4x-2=8

5x=10

X=2

Y=2(2)-1

Y=3

d)X+3Y=15- - - - - - - - - - - equation 1

2X-2=Y

Substitute Y in equation 1

X+3(2X-2)=15

X+6X-6=15

7X=21

X=3

Y=2(3)-2

Y=4

e)X+Y=6 - - - - - - - - - - - equation 1

2X=Y

Substitute Y in equation1

X+2X=6

3X=6

X=2

Y=2(2)

Y=4