Answer:
Explanation:
d ) 13x−8y=28 11x−8y=24
we can solve:
13x−8y=28
11x−8y=24
.............................(subtract side by side)
13x - 11 x + (-8y) - (-8y) = 28 - 24
2x + 0 = 4
x = 4/2 = 2 (divide both sides by 2),
then you replace x = 2 into 13x - 8y = 28, we have 26 - 8y = 28
or -8y = 28-26, or -8y = 2, then y = 2/ -8= -1/4
Solution x =2, y = - 1/4
b) 5x−2y=1 15x−3y=−3
5x−2y=1 (multiple bothe sides by 3)
15x−3y=−3
we have
15x−6y=3
15x−3y=−3
..................( subtract side by side)
0 -3y = 6
y = 6/-3
y = -2
then you replace y =- 2 into 5x - 2y = 1, we have 5x + 4 = 1
or 5x = 1-4 or 5x = -3, then x = -3/5
Solution: x = -3/5, y = -2
c) 13x−12y=14 11x−4=18y
we have:
13x−12y=14
11x−4=18y
then:
13x−12y=14 ( multiple bothe sides by 6)
11x - 18y = 4 (multiple bothe sides by 4)
then
78x−72y=84
44x−72y= 16
...........................( subtract side by side)
34x = 68
or x = 68/34 = 2
then you replace x = 2 into 11x -4 = 18y , we have 22 -4 = 18y
or 18y = 18 or y = 18/18 = 1
Solution: x = 2 , y = 1
a) 12x−7y=2 4x−5y=6
we have
12x−7y=2
4x−5y=6 (multiple bothe sides by 3)
so
12x−7y=2
12x−15y=18
-------------------------(subtract side by side)
8y = -16
or y = -16/8 = -2
then you replace y = -2 into 4x -5y = 6 , we have 4x + 10 = 6
or 4x = 6 - 10 or 4x = - 4 and x = -4/4 = - 1
Solution: x = - 1 , y = - 2
b) 7u+2v=1 17u+6v=−9
7u+2v=1 (multiple bothe sides by 3)
17u+6v=−9
so
21u+6v=3
17u+6v=−9
------------------(subtract side by side)
4u = 12
or u = 12/4 = 3
then you replace u = 3 into 7u +2v = 1 , we have 21 + 2v = 1
or 2v = 1 - 21 or 2v = - 20 and v = -20/2 = - 10
Solution: u = 3, v = - 10
c) 6x=25y+1 5x−16y=−4
6x=25y+1 (multiple bothe sides by 5)
5x−16y=−4 (multiple bothe sides by 6)
we have
30x=125y+5
30x = 96y−24
-------------------------(subtract side by side)
0 = 29y + 29
or 29y = - 29
then y = - 29/29 = -1
then you replace y = -1 into 6x = 25y + 1 , we have 6x = - 25 + 1
or 6x = - 24 or x = -24/6 = - 4
Solution: x= -4, y = - 1
Have a good day!