Question

Tolong ini kakak math

No. 1
Himpunan penyelesaian dari sistem persamaan 4x + 7y = 5 dan x + y = –1 adalah ....
a. {(–4, 3)}
b. {(3, –4)}
c. {(4, –3)}
d. {(–3, 4)}

No. 2.
Himpunan penyelesaian dari sistem persamaan y = 2x + 1 dan 3x – 5y = 16 adalah ....
a. {(–3, 5)}
b. {(5, 3)}
c. {(–3, –5)}
d. {(–5, 3)}

Poinya besar kak

Answer 1

Verified answer

1.]
x + y = -1
x = -1 - y

Maka
4(-1 - y) + 7y = 5
-4 - 4y + 7y = 5
3y = 9
y = 3

x = - 1 - 3
x = -4

HP : {(-4 , 3)} A

2.]
y = 2x + 1

Maka
3x - 5(2x + 1) = 16
3x - 10x - 5 = 16
-7x = 21
x = -3

y = 2(-3) + 1
y = -5

HP : {(-3 , -5)} C

Answer 2

Nomor 1

4x + 7y = 5
x + y = -1

4x + 7y = 5
4x + 4y = -4
----------------- -
3y = 9 x + 3 = -1 (a)
y = 3 x = -4

nomor 2

y = 2x + 1
3x -5y = 16

3x -5(2x+1) = 16
3x -10x -5 = 16

-7x = 21 y = -6 + 1 (c)
x = -3 y = -5