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If

(20 y+5)(4y-30)=80y^(2)+by
for all values of 
y where 
b is a constant, then which of the following is the value of 
b ?
Choose 1 answer:
(A) -580
(B) -40
(c) 0
(D) 620

If\newline(20y+5)(4y30)=80y2+by (20 y+5)(4 y-30)=80 y^{2}+b y \newlinefor all values of y y where b b is a constant, then which of the following is the value of b b ?\newlineChoose 11 answer:\newline(A) 580-580\newline(B) 40-40\newline(C) 00\newline(D) 620620

Full solution

Q. If\newline(20y+5)(4y30)=80y2+by (20 y+5)(4 y-30)=80 y^{2}+b y \newlinefor all values of y y where b b is a constant, then which of the following is the value of b b ?\newlineChoose 11 answer:\newline(A) 580-580\newline(B) 40-40\newline(C) 00\newline(D) 620620
  1. Expand left side using distributive property: First, we will expand the left side of the equation using the distributive property (also known as the FOIL method for binomials).\newline(20y+5)(4y30)=80y2+by(20y + 5)(4y - 30) = 80y^2 + by\newlineExpanding gives us:\newline20y×4y+20y×(30)+5×4y+5×(30)20y \times 4y + 20y \times (-30) + 5 \times 4y + 5 \times (-30)
  2. Perform multiplication for each term: Now, we will perform the multiplication for each term.\newline20y×4y=80y220y \times 4y = 80y^2\newline20y×(30)=600y20y \times (-30) = -600y\newline5×4y=20y5 \times 4y = 20y\newline5×(30)=1505 \times (-30) = -150\newlineSo, the expanded form is:\newline80y2600y+20y15080y^2 - 600y + 20y - 150
  3. Combine like terms on the left side: Next, we combine like terms on the left side of the equation.\newline80y2600y+20y150=80y2+by80y^2 - 600y + 20y - 150 = 80y^2 + by\newlineCombining the yy terms gives us:\newline80y2580y150=80y2+by80y^2 - 580y - 150 = 80y^2 + by
  4. Equating coefficients of yy: Since the equation must hold for all values of yy, the coefficients of the corresponding yy terms on both sides of the equation must be equal. This means that the coefficient of yy on the left side must be equal to bb on the right side.\newlineTherefore, 580y=by-580y = by
  5. Find the value of b: We can now equate the coefficients of y from both sides to find the value of b.\newline580-580 = b
  6. Find the value of b: We can now equate the coefficients of y from both sides to find the value of b.\newline580-580 = bWe have found the value of b, which is 580-580. This corresponds to answer choice (A).