Answer:
c .3.3
Step-by-step explanation:
pH is the negative log of the molar hydrogen ion concentration.The equation to calculate pH is;
pH = -log10[H+]
pH = -log10(5.0 x 10-4)
pH = 3.30
 
        
                    
             
        
        
        
Solve for x in 2nd equation
times -1 both sides
x-5=6y
add 5
x=6y+5
sub
5(6y+5)+4y=-26
30y+25+4y=-26
34y+25=-26
minus 25 both sides
34y=-51
divide both sides by 34
y=-3/2
sub back
x=6y+5
x=6(-3/2)+5
x=-18/2+5
x=-9+5
x=-4
(-4,-3/2) is solution
        
                    
             
        
        
        
Answer:
The answer is x=20
Step-by-step explanation:
27-7=20 
x=20