The ratio of boys to girls in Mr. Johnson’s after-school club is the same as the ratio of boys to girls in Ms. Greene’s after-school club. There are 4 boys and 12 girls in Mr. Johnson’s club. There are 6 boys in Ms. Greene’s club. How many girls are in Ms. Greene’s club? 2
12
14
18

Aline passes through 3,7 and 6,9 what equation represents the line

Given that abcd is a rhombus, what is the value of x?

Prove (a) cosh2(x) − sinh2(x) = 1 and (b) 1 − tanh 2(x) = sech 2(x). solution (a) cosh2(x) − sinh2(x) = ex + e−x 2 2 − 2 = e2x + 2 + e−2x 4 − = 4 = . (b) we start with the identity proved in part (a): cosh2(x) − sinh2(x) = 1. if we divide both sides by cosh2(x), we get 1 − sinh2(x) cosh2(x) = 1 or 1 − tanh 2(x) = .