What is the price then I will help you comment me and I will give you the answer sorry I can not do more right now );
Q.17)

Q.18

Q.19

Q.20

Q.21

For the 17 times 5 part, a easy way to do it is to times 17 by 10, then divide by 2. (since 5 = 10 divided by 2)
So 17 x 10 = 170
170 / 2 = 85
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If you have any questions, don't hesitate to ask : )
Answer:
y = -x +4
Step-by-step explanation:
2x+5y = 3y+8
Subtract 3y from each side
2x+5y-3y = 3y-3y+8
2x+2y = 8
Subtract 2x from each side
2x+2y -2x = -2x+8
2y = -2x+8
Divide by 2
2y/2 = -2x/2 +8/2
y = -x +4