6.r_xaxis=(x,-y)
7.first option
I might be wrong but I think the answer would be -x+2x+6 as a simplified version because if you use the equation (x+4•x+3)-3x(x+1)=a (or any letter you choose), you will get 3x+x^2+12+4x-3x-3x^2=y. Then, you can combine like terms:
4x-2x+12=a
Answer:
x=3.5
Step-by-step explanation:
subract 5 on the other side, than divide by 2
