We have to solve this quadratic equation for n to get <em>which figure has 56 blocks</em>.
For middle term factorization, we need <em>two numbers that multiplied gives us -56 and added gives us 1 (coefficient of n).</em>
<em>Such two numbers are </em><em>8</em><em> and </em><em>-7</em><em>. We can now write,</em>
<em></em>
<u><em>"There is no negative figure number possible, so we disregard -8"</em></u>
Our answer is 7.
ANSWER: The 7th figure has 56 blocks.