Find the value(s) of p for which the quadratic equation given as: (p+4)x2−(p+1)x+1=0(p+4)x² - (p+1)x + 1=0 has real and equal roots. Also, find the roots of the equation(s) so obtained

Answer: The values of pp are 55 and −3-3. When p=5p = 5, the roots are 13,13\frac{1}{3}, \frac{1}{3}. When p=−3p = -3, the roots are −1,−1-1, -1.

Step-by-step solution

Step 1: Identify coefficients of the quadratic equation

Comparing the given equation (p+4)x2−(p+1)x+1=0(p+4)x^2 - (p+1)x + 1 = 0 with the standard form ax2+bx+c=0ax^2 + bx + c = 0, we identify a=p+4a = p + 4, b=−(p+1)b = -(p + 1), and c=1c = 1. Since it is a quadratic equation, the coefficient of x2x^2 cannot be 0, so p≠−4p \neq -4.

Step 2: Set the discriminant to zero for equal roots

A quadratic equation has real and equal roots if and only if its discriminant b2−4ac=0b^2 - 4ac = 0. Substituting the values of aa, bb, and cc, we set up the equation for pp.

Step 3: Solve the equation for p

Expanding the discriminant expression gives (p2+2p+1)−(4p+16)=0(p^2 + 2p + 1) - (4p + 16) = 0, which simplifies to p2−2p−15=0p^2 - 2p - 15 = 0. Factoring this quadratic equation gives (p−5)(p+3)=0(p - 5)(p + 3) = 0, so p=5p = 5 or p=−3p = -3. Both values satisfy p≠−4p \neq -4.

Step 4: Find the roots when p=5p = 5

For p=5p = 5, the quadratic equation becomes 9x2−6x+1=09x^2 - 6x + 1 = 0. When the discriminant is 0, the equal roots are given by −b2a-\frac{b}{2a}. Here, x=−−62(9)=13x = -\frac{-6}{2(9)} = \frac{1}{3}, so the roots are 13,13\frac{1}{3}, \frac{1}{3}.

Step 5: Find the roots when p=−3p = -3

For p=−3p = -3, the quadratic equation becomes x2+2x+1=0x^2 + 2x + 1 = 0. Using the formula for equal roots −b2a-\frac{b}{2a}, we get x=−22(1)=−1x = -\frac{2}{2(1)} = -1, so the roots are −1,−1-1, -1.

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