Answer:

Step-by-step explanation:
We must develop three equations in three unknowns.
I will use these three:



Answer:
I am unable to solve this problem Sorry
Step-by-step explanation:
Answer:
Step-by-step explanation:
Edith is x years old.
Her sister,Madison is six years older than her. This means that the age of Madison is x + 6
Their mother is twice as old as Madison. This means that the age of their mother is expressed as
2(x + 6)
= 2x + 12
Their aunt, Elizabeth is x years older than their mother. This means that the expression that represents Elizabeth's age in years is
2x + 12 + x
= 3x + 12
Distribute 1st or subtract 90 and 3 first and then multiply by 15
(9x^4-13x^3-x-7)+(7x^3-2x+1)=
9x^4-13x^3-x-7+7x^3-2x+1=
9x^4+(-13+7)x^3+(-1-2)x-7+1=
9x^4+(-6)x^3+(-3)x-6=
9x^4-6x^3-3x-6
Answer: Option <span>D.)9x^4−6x^3−3x−6</span>