Question

Find the value of x, if 5x = (50)² − (40)².

Answer 1

 Let us consider the following equation: \[5x = \left( 50 \right)^2 - \left( 40 \right)^2\]

Using the identity \[\left( a + b \right)\left( a - b \right) = a^2 - b^2\], we get:

\[5x = \left( 50 \right)^2 - \left( 40 \right)^2 \]

\[5x = \left( 50 + 40 \right)\left( 50 - 40 \right)\]

\[5x = 90 \times 10 = 900\]

\[\Rightarrow 5x = 900\]

\[\Rightarrow x = 180\]       (Dividing both sides by 5)