aa+(a3)=180

Question

i need help with this

Answer 1

I read this as a*a+a*3=180. If that's right it can also be written: a^2+3a=180 or a^2+3a-180=0.

This quadratic equation factorises into (a-12)(a+15)=0 because 15a-12a=3a and -12 * 15=-180.

So either a-12=0, making a=12 or a+15=0, making a=-15. Both solutions are needed.

CHECK

12*12+12*3=144+36=180 OK

-15*-15+(-15)*3=225-45=180 OK