Answer:
She should have multiplied by 4, not divided
Step-by-step explanation:
Given
 - 11 = 13 ( add 11 to both sides ) ← correct
 - 11 = 13 ( add 11 to both sides ) ← correct
 = 24 ( multiply both sides by 4 to clear the fraction )
 = 24 ( multiply both sides by 4 to clear the fraction )
H = 4 × 24 = 96
H is divided by 4, thus the inverse operation is to multiply
 
        
             
        
        
        
Answer:
9
Step-by-step explanation:
Replace a by 7
and 
b by 4
and 
c by 1/2
7+4(1/2)
7+2=9
 
        
             
        
        
        
15x-6+x-3=39
16x-9=39
16x=39+9
16x=48
x=48/16
x=3