$\displaystyle xy=8$ $\displaystyle x^2+y^2=10$ $\displaystyle (x+y)^2= ?$ Please explain.
Follow Math Help Forum on Facebook and Google+
Originally Posted by sk8teroy $\displaystyle xy=8$ $\displaystyle x^2+y^2=10$ $\displaystyle (x+y)^2= ?$ Please explain. Expand: $\displaystyle (x + y)^2 = x^2 + 2xy + y^2 = 2xy + x^2 + y^2$. Now substitute $\displaystyle xy=8 \, $ and $\displaystyle \, x^2+y^2=10$ .....
View Tag Cloud