PERFECT SQUARES 2

If zx² - 28x + 49 = 0 is a perfect square, find the value of z .

Solution

In zx² - 28x + 49 = 0;   a=z, b=-28 and c=49.

For the perfect square, b² = 4ac

(-28)² = 4 x z x 49

784 = 196z

  

 784 =     196z

196    196

4 = z

Hence the value of z is 4

TRY THIS...................

If zx² - 24x + 16 = 0 is a perfect square, find the value of z .