7. 4x+y=8 ----- first equation
(+)
-3x-y=0
_______
x = 8 ---- second equation
substitude second equation into first equation
4(8) + y = 8
32 + y = 8
y = 24
8. 2x+5y=20 ---- first equation
(-)
2x-5y =3
________
10y = 17
y = 17/10 ---- second equation
substitude second equation into first equation
2x + 5(17/10) = 20
2x + 17/2 = 20
4x + 17 = 40
4x = 23
x = 23/4
9. 3x+2y=-10 (×2) ---- first equation
2x-5y=3 (×3)
6x + 4y = - 20
(-)
6x - 15y = 9
___________
19y = - 29
y = - 29/19 ---- second equation
substitude second equation into first equation
3x + 2(-29/19) = - 10
3x - 58/19 = - 10
3x = - 132/19
x = - 44/19
3/3 I THIB=NKKKKKKKKKKKKKKKKKKKKKKKKK
Answer:
4 option D
Step-by-step explanation:
Note that log2(2^n)=n
Thus we have:
Log2(2)+log2(8)=1+log2(2³)=1+3=4
