−2 1/4=r−4/5

Help

Plz

r=-29/20

Step-by-step explanation:

because

-2 1/4 will be -9/4=r-2/5 now you add 2/5 to both sides

witch means you have to increase the denominator to the greatest common denominator of 4 and 5 witch is 20 multiply the number used to combine with the denominator to get 20 to the numerator so itll be -45/20+16/20 witch will be -29/20 so there fore r=-29/20 or 1 9/20.

answer: i realy don't get it that much can you me figer it out pleas you

step-by-step explanation:

(b) 240

step-by-step explanation:

first, we use the pythagorean formula using the given side lengths to find x. then we use x to find the side lengths. then we add the side lengths to find the perimeter.

pythagorean theorem formula:

a^2 + b^2 = c^2

(x - 20)^2 + (x - 40)^2 = x^2

x^2 - 40x + 400 + x^2 - 80x + 1600 = x^2

x^2 -120x + 2000 = 0

(x - 100)(x - 20) = 0

x - 100 = 0 or x - 20 = 0

x = 100 or x = 20

we see that the solution x = 20 must be discarded because it will give a negative side length and a side length of 0. the only valid solution is x = 100.

perimeter = sum of the lengths of the sides

perimeter = x + x - 20 + x - 40

perimeter = 3x - 60

replace x with 100.

perimeter = 3(100) - 60

perimeter = 300 - 60

perimeter = 240