An equilateral triangle has a perimeter of 21 and a side length of 2x - 3. solve for x

In any triangle, Perimeter (P) = a + b + c, where, a, b and c are the sides  and P is the perimeter of the triangle

In case of equilateral triangle, the length of all sides are equal. Therefore,

P = a + a + a = 3a

Here, a = (2x - 3) and P = 21

or, 21 = 3 (2x - 3)

or, 7 = 2x - 3

or, 2x = 10

or, x = 5

x > 1.3

step by step:

8.5−0.9x> 9.8−1.9x

step 1: simplify both sides of the inequality.

−0.9x+8.5> −1.9x+9.8

step 2: add 1.9x to both sides.

−0.9x+8.5+1.9x> −1.9x+9.8+1.9x

1x+8.5> 9.8

step 3: subtract 8.5 from both sides.

1x+8.5−8.5> 9.8−8.5

1x> 1.3

step 4: divide both sides by 1.

1x/1 > 1.3/1