If the product of the zeroes of the quadratic polynomial 5x2+7x+k5x^2 + 7x + k is −25- \frac{2}{5}, then the value of k is :

Answer: The value of kk is −2-2.

Step-by-step solution

Step 1: Identify coefficients of the quadratic polynomial

A general quadratic polynomial is given by ax2+bx+cax^2 + bx + c. We need to compare the given polynomial 5x2+7x+k5x^2 + 7x + k with this general form to identify the coefficients aa, bb, and cc.

Step 2: State the formula for the product of zeroes

For a quadratic polynomial ax2+bx+cax^2 + bx + c, the product of its zeroes (roots) is given by the formula ca\frac{c}{a}. This is a fundamental property of quadratic equations.

Step 3: Substitute the given values into the formula

From the given polynomial 5x2+7x+k5x^2 + 7x + k, we have a=5a=5 and c=kc=k. We are also given that the product of the zeroes is −25- \frac{2}{5}. Substituting these values into the formula for the product of zeroes, we get the equation k5=−25\frac{k}{5} = -\frac{2}{5}.

Step 4: Solve for k

To find the value of kk, we need to solve the equation k5=−25\frac{k}{5} = -\frac{2}{5}. We can multiply both sides of the equation by 5 to isolate kk.

More from this chapter

All Polynomials solutions →

Solve your own maths question free →