Answer:
The answer is 5a-35.
Step-by-step explanation:
So, since you told me to explain, if a number is right next to a parentheses without any signs you multiply it.
But instead of doing 5 times 7a, you multiply both of them separately.
5 times a is pretty much just 5a. 5 times -7 is -35.
As a result, you will be left with 5a-35.
If you have anymore questions, let me know.
<u>ANSWER </u>

<u>EXPLANATION</u>
We the have the equations,

Multiplying through by negative one gives,

Also

and

Dividing through by 2 gives

Making z the subject gives,

Now we substitute equation (3) into equation (1) and (2)
Equation (3) in to equation (1) gives,

This implies that;


We now put equation (3) in (2) to get,

This implies that



But

So,




Dividing through by negative 9 gives

and


Therefore 
Y= 2x+1
The slope is 2/1 which can be written as 2. The line crosses the y-axis at 1, so it will be the +1
Answer:
HL
Step-by-step explanation:
PQ = PR {hypotenuse}
PS = PS {Reflexive property, PS is the leg of the both triangles}
∠PSQ = ∠PSR = 90
So, HL postulate
The gradient is 2.
You divide the increase in y (2) by the increase in x (1)