The amount of sales tax would be 1.75$
1 to 5 you most likely have to add 36 x the number but the fractions I don't know
So you will need to solve for x and y before evaluating 2x+y....
2x-y=9, y=2x-9 now this will make 4x^2-y^2=171 become:
4x^2-(2x-9)^2=171
4x^2-(4x^2-36x+81)=171
36x-81=171
36x=252
x=7, now we can use 2x-y=9 to solve for y...
2(7)-y=9
14-y=9
-y=-5
y=5
now we know that x=7 and y=5, 2x+y becomes:
2(7)+5
14+5
19
9x² + 7y² = 42
7y² = 42 - <span>9x²
</span>
y² = (42 - <span>9x²)/7</span>
Answer:
842688 or 83
Step-by-step explanation:
