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
Answer:
Hi
Step-by-step explanation:
The answer is 6.1 = 6 1/10
Let b>a,
a+b=40 so we can say a=40-b
We are told that b-a=6.5, using a found above in the equation gives us:
b-(40-b)=6.5
b-40+b=6.5
2b-40=6.5
2b=46.5
b=23.25, and since a=40-b
a=40-23.25
a=16.75
So a=16.75 and b=23.25
check...
16.75+23.25=40, 40=40
23.25-16.75=6.5, 6.5=6.5
