Answer:
first, second and fourth are all correct
Step-by-step explanation:
I don’t know if I’m correct but:
120➗100=1.2
Which could mean that the x could be 1.2
(I’m not sure because I haven’t done this in a long time)
(Sorry if it’s wrong)
The 'i' should go in front of the square root, not inside it.
So the answer should be 
--------------
The way they wrote the expression 
is bit misleading as it might imply that the 'i' is under the square root. However the square root ends after the "5". It might be better to say 
so there is clearer separation. But sticking the "i" in front is also a valid option.
side note: the plus minus part is already handled so there's no need to worry about that.
Simplify each term.
1/2X - 1/3Y
Combine 1/2x and −1/3y using a common denominator.
To write −1/3y as a fraction with a common denominator, multiply by 2x/2x.
(1 / 2x )(3y / 3y) + (−1 / 3y) (2x / 2x)
Write each expression with a common denominator of 6xy, by
multiplying each by an appropriate factor of 1.
1 (3y)/6xy − 1 (2x)/6xy
Combine the numerators over the common denominator.
1(3y) − (1(2x))/6xy
Simplify the numerator.
3y−(1(2x))/6xy
<span>Simplify.
</span>3y−(2x)/6xy
<span><span>3y−2x/</span><span>6xy</span></span>
Simplify with factoring<span> out.
</span>
Reorder <span>3y</span><span> and </span><span><span>−2x</span>.</span>
<span><span>−2x+3y/</span><span>6xy</span></span><span>
</span>
Factor <span>−1</span><span> out of </span><span><span>−2x</span>.</span>
<span><span>−1(2x)+3y/</span><span>6xy</span></span>
Factor <span>−1</span><span> out of </span><span><span>3y</span>.</span>
<span><span>−1(2x)−1(−3y)/</span><span>6xy</span></span><span>
</span>
Factor <span>−1</span><span> out of </span><span><span>−1(2x)−1(−3y)</span>.</span>
<span>−1(2x−3y)/</span><span>6xy
</span>Move the negative in front of the fraction<span>.
</span>
<span>−<span><span>2x−3y/</span><span>6xy</span></span></span><span>
</span>
The answer is 5x+50=y
Because you have to pay 50 dollars to get a lesson you have to pay it plus the number of lessons multiplied by the price.
