Which values of c will cause the quadratic equation -x2+3x+c=0

Leo has b boxes of pencils. each box contains 6 pencils. he has a total of 42 pencils. the equation that represents this situation the value of b that makes the equation true the first one is b+6=42,6b=42,b=42+6,or 42b=6 the second one are 7,836 48

We just started the introduction into circles and i have no idea how to do this.

How are sas and sss used to show that two triangles are congruent?