Balance the equation: HCl + Mg(OH)_2 --> MgCl_2 +H_2O
First count the number of atoms of each element. Always balance the most common elements like H,O,C at the end. Balance Cl and Mg first. Both sides have only 1 Mg so they are balanced. The left side only has 1 Cl while the right has 2. Hence multiply HCl by 2. This gives us 4 H's on the left and only 2 on the right. As a result, multiply H_2O by 2. This also balances the O's. The result is: 2HCl + Mg(OH)_2 --> MgCl_2 + 2H_2O
Use the chain rule to calculate derivative of: y=(5x+1)^3
This rule involves taking the derivative of the terms inside the bracket, multiplying it with the power of the term and original term with its power decreased by 1. dy/dx=3(5)(5x+1)^2
Find the equation of the line A that passes through the point ( 2 ,1 ) and is perpendicular to the line B 2x + y = 4 .
Line B has a gradient of -2. Since the two lines are perpendicular, the products of their gradient would be -1. mA*mB=-1 mA*-2=-1 mA=0.5 Use equation y-y1= mA(x-x1) y1=1, x1=2 y-1= 0.5(x-2) y-1=0.5x-1 y=0.5x :Line A