A and B are in quadrant 1. Sin A = (4/5) and cos B = (7/9). Give an exact value for Sin (A+B).

Given N_2(g)+O_2(g)<--> 2NO_(g) Keq=8.00 *10^-2 at 500 C

In a 2.00L flask, 0.4 mol of N₂ and 0.4 mol of oxygen gas, O₂, reacted to equilibrium. Establish the equilibrium concentration of all the gases.

(Answer: [N₂]=0.175 mol/L; [O₂] = 0.175 mol/L; [NO] = 0.0496 mol/L) This one has got a quadratic I can't figure out 

My first step: $\frac{\left(2x\right)}{\left(0.2-x\right)^2}=0.08$‍(2x)(0.2−x)² =0.08 

My second step:  $0.08\cdot\left(.2-x\right)\left(.2-x\right)=2x$0.08·(.2−x)(.2−x)=2x 

Don't know what's next

Given the reaction PCl₅(g)<--> PCl₃(g)+Cl_2(g)

In a 1.00 L flask, 0.72 mol of PCl₅ and 0.18 mol of PCl₃ are mixed together. Reaction occurrred to equilibrium and tests showed that 0.60 mol of PCl₅ was now present. Calculate the Keq value.

(Answer: 6.0*10^-2)although I cannot figure out how to find this without a given value from Cl_2.

  write  $2\log_bx-\frac{\log_bZ}{2}$2 log_bx− log_bZ2   as a single logarithm

if Y=f(x) is reflected in the x-axis, stretched horizontally by a factor of 1/2 and stretched vertically by a factor of 2, what is the new equation?

Given  $ Y-k=a\ left(x-h\ right)^2$ Y−k=a(x−h)² , a=1, h<0, k>0, which quadrant  is the vertex in?  

 I've been trying to figure out why  $f\ left(x\ right)=\ SQRT{x+2}$ƒ (x)=√x+2  IS a shift left 2.  I keep thinking that it IS +2 and that means right 2.