Answer: 47
Explanation:
Dude just subtract 43 from 90, since you are given a 90 degree angle.
But if you need the equation: 43+x-7=90
add 43 and (-7) which gives us 36
new equation is now: 36+x=90
move the 36 to the other side
x=54
now plug it in x(54)-7=47