hey i can't figure this one out, does anyone know the answer?
Question: Shenika factored the polynomial completely. What is the value of A?
5x3+35x2+6x+42
(5x2+A)(x+B)
A. 1
B. 5
C. 6
D. 7
(if anyone is confused why this question is written weird, i don't know why its like that either)
3 answers
(and yes, im this bad at math)
Nothing at all wrong with this question, nor the way it is written
so you have:
(5x^2+A)(x+B) = 5x^3+35x^2+6x+42 , ..... notice how I wrote the powers.
expand the left side:
5x^3 + 5Bx^2 + Ax + AB
match the terms:
5x^3 <----> 5x^3
5Bx^2 <----> 35x^2 , so 5B = 35, then B = 7
Ax <----> 6x , then A = 6
AB <----> 42 , true since AB = 6*7 = 42
A = 6
B = 7 , so C is your correct choice
check, sub those values into the factored form,
(5x^2+6)(x+7)
= 5x^3 + 35x^2 + 6x + 42 , which is the expanded form given
So, my answer is correct
so you have:
(5x^2+A)(x+B) = 5x^3+35x^2+6x+42 , ..... notice how I wrote the powers.
expand the left side:
5x^3 + 5Bx^2 + Ax + AB
match the terms:
5x^3 <----> 5x^3
5Bx^2 <----> 35x^2 , so 5B = 35, then B = 7
Ax <----> 6x , then A = 6
AB <----> 42 , true since AB = 6*7 = 42
A = 6
B = 7 , so C is your correct choice
check, sub those values into the factored form,
(5x^2+6)(x+7)
= 5x^3 + 35x^2 + 6x + 42 , which is the expanded form given
So, my answer is correct
Ah thanks so much!
3 answers