Question

I need to find what x

Answer 1

x = 16, x = -7

Explanation:

The question is;

35 * 4 = ( x - 7 ) ( x - 3 )

Combine like terms on one side;

140 = ( x - 7 ) ( x - 3 )

Distribute, remember to multiply every term with one another;

140 =
`x^(2)` - 3x - 7x + 21

Combine like terms;

140 =
`x^(2)` - 10x + 21

Inverse operations;

140 =
`x^(2)` - 10x + 21

-21 -21

119 =
`x^(2)` - 10x

Factor;

119 = x ( x - 10 )

At this point it is fairly obvious that;

x = 16, x = -7

Note; One could have used a multitude of methods to solve this problem, one could have factored, completed the square, or used the quadratic formula, this method was simply chosen because it is easy to explain

Answer 2

Explanation:

Add the 21 then divide by 2