Bytelearn - cat image with glassesAI tutor

Welcome to Bytelearn!

Let’s check out your problem:

It is given that 10x^(3)+5x^(2)-x+4=(2x-1)(x+3)Q(x)+Ax+B, where Q(x) is a polynomial. Find the values of the constants A and B.

It is given that 10x3+5x2x+4=(2x1)(x+3)Q(x)+Ax+B 10 x^{3}+5 x^{2}-x+4=(2 x-1)(x+3) \mathrm{Q}(x)+A x+B , where Q(x) \mathrm{Q}(x) is a polynomial. Find the values of the constants A A and B B .

Full solution

Q. It is given that 10x3+5x2x+4=(2x1)(x+3)Q(x)+Ax+B 10 x^{3}+5 x^{2}-x+4=(2 x-1)(x+3) \mathrm{Q}(x)+A x+B , where Q(x) \mathrm{Q}(x) is a polynomial. Find the values of the constants A A and B B .
  1. Understand Polynomial Division: Understand the division of polynomials.\newlineThe given equation is a polynomial division where the dividend is 10x3+5x2x+410x^3 + 5x^2 - x + 4 and the divisor is (2x1)(x+3)(2x - 1)(x + 3). The quotient is Q(x)Q(x) and the remainder is Ax+BAx + B. To find AA and BB, we need to perform polynomial long division or synthetic division.
  2. Set Up Division: Set up the division.\newlineSince Q(x)Q(x) is a polynomial and we are given that the remainder is linear (of the form Ax+BAx + B), we can infer that Q(x)Q(x) must be of degree 11 (since the degree of the dividend is 33 and the divisor is 22). Let's denote Q(x)=Cx+DQ(x) = Cx + D where CC and DD are constants to be determined.
  3. Multiply Divisor by Quotient: Multiply the divisor by the assumed quotient.\newlineWe multiply (2x1)(x+3)(2x - 1)(x + 3) by Q(x)=Cx+DQ(x) = Cx + D to get the part of the dividend that is divisible by the divisor.\newline(2x1)(x+3)(Cx+D)=(2Cx2+(6CD)xD)(x+3)(2x - 1)(x + 3)(Cx + D) = (2Cx^2 + (6C - D)x - D)(x + 3)\newlineNow we expand this product to find the coefficients that will match the dividend.
  4. Expand and Equate Coefficients: Expand the product and equate coefficients.\newlineExpanding the product, we get:\newline2Cx3+(6CD)x2Dx+2Cx2+(6CD)xD2Cx^3 + (6C - D)x^2 - Dx + 2Cx^2 + (6C - D)x - D\newlineCombining like terms, we have:\newline2Cx3+(6CD+2C)x2+(6CDD)xD2Cx^3 + (6C - D + 2C)x^2 + (6C - D - D)x - D\newlineThis simplifies to:\newline2Cx3+(8CD)x2+(6C2D)xD2Cx^3 + (8C - D)x^2 + (6C - 2D)x - D\newlineNow we equate the coefficients of this expression to the coefficients of the dividend 10x3+5x2x+410x^3 + 5x^2 - x + 4.
  5. Equate x^33 Coefficients: Equate the coefficients of the x^33 terms.\newlineFrom the x^33 terms, we have:\newline2C=102C = 10\newlineSolving for CC, we get:\newlineC=5C = 5
  6. Equate x^22 Coefficients: Equate the coefficients of the x^22 terms.\newlineFrom the x^22 terms, we have:\newline8CD=58C - D = 5\newlineSubstituting C=5C = 5 into this equation, we get:\newline8(5)D=58(5) - D = 5\newlineSolving for DD, we get:\newline40D=540 - D = 5\newlineD=405D = 40 - 5\newlineD=35D = 35
  7. Realize and Correct Mistake: Realize the mistake and correct it.\newlineWe made a mistake in the previous step. We should have equated the coefficients of the x^22 terms to the dividend's x^22 coefficient, which is 55. However, we incorrectly equated 8CD8C - D to 55 instead of 8CD8C - D to the dividend's x^22 coefficient. Let's correct this.

More problems from Composition of linear and quadratic functions: find an equation