Question

What value of n makes the equation true? (2x^9y^n)(4x^2y^10)=8x^11y^20

Answer 1

Hi there! The answer is n = 10.

$(2 {x}^{9} {y}^{n} )(4 {x}^{2} {y}^{10} ) = 8 {x}^{11} {y}^{20}$

As you see at the powers of x, we need to add the exponents of the power we when multiply them.
${x}^{9} \times {x}^{2} = {x}^{9 + 2} = x {}^{11}$

The powers of y work the same way.
${y}^{n} \times {y}^{10} = {y}^{n + 10} = {y}^{20}$

Hence, n = 10, since
${y}^{10 + 10} = {y}^{20}$