They are both simple exercises in addition.
The solutions are:
(-65) x (-2) = <em>130</em>
(5j) + (10j) =<em> 15j</em>
Answer:
AC is equal to BA and BC is equal to CB
Since B is perpendicular to A. We can say that the gradient of B will be -1/7 (product of the gradients of 2 perpendicular lines has to be -1).
Now we know that the equation for B is y=-(1/7)x + c with c being the y intercept.
Since the point isnt specified in the question, we could leave the equation like this.
But if there is a given point that B passes through, just plug in the x and y values into their respective places and solve to find c. That should give you the equation for b.
Now, to find the solution of x, we have 2 equations:
1) y=7x+12
2)y=-(1/7)x+c
In this simultaneous equation we see that y is equal to both the expressions. So,
7x+12=-(1/7)x+c
Now, since the value of c is not found, we cannot actually find the value of x, but if we would find c, we could also find x since it would only be a matter of rearranging the equation.
And there you go, that is your solution :)
Use tan because you are dealing with the opposite and adjacent sides
