7 = r^1/2 is the same as saying 7 = square root of r. So, to get rid of the square root sign on the r, you need to square it, and when you do something to one side of the equation, you have to do the same to the other side. So after squaring both sides, you get 49 = r.
Answer: Infinite solutions
Step 1: Turn this into y=Mx+b form
The current equation is—
-2x+5y=30
Since we want to get y alone on the left side, let’s add 2x on both sides
-2x+5y=30
+2x +2x
____________
5y=2x+30
Step 2: Again, trying to get y alone, we need to divide 5 on both sides
5y=2x+30
/5 /5 /5
________
y=2/5x+6
Step 3: Now that we know how to find y, substitute that in where y is in the equation
-2x + 5(2/5x+6) = 30
-2x + 2x + 30 = 30
30=30
Seeing that you cannot get a specific answer for y when solving, there is an infinite number of solutions
Hope this is right and it helps comment below for more questions :)
