Answer:
x=40
Step-by-step explanation:
you have to get a answer of 60
(40)+20=60
and 2(40)-20=60
a(x+1)(x-1)+b(x-2)(x+1)+(x+1)^2=9x^2-x-10
(x+1)(a(x-1)+b(x-2)+(x+1))=(x+1)(9x-10)
a(x-1)+b(x-2)+x+1=9x-10
Now this equation is much simpler!
(a+b)x-a-2b+x+1=9x-10
(a+b)x-a-2b=8x-11
(a+b-8)x-a-2b-11=0
a+b-8=(a+2b-11)/x
I can't solve it 3 variables and 1 equations means infinite answers so yea.
Let's call the width: w
the lenght is then 3w+4 ("4 more than 3 times the width")
and the parameter would be 2(w+3w+4), that is 2*(4w+4), that is 8w+8.
this is also equal to 18.4:
8w+8=18.4
8w=10.4
w=1.3
this is the width, and the lenght is:
4+3*1,3=4+3.9=7.9
and the area is their product:
1.3*7.9=10.27
I think the answer is b and c but I’m not very sure
