Answer:
13
Step-by-step explanation:
The perimeter is calculated by multiplying the sum of width and height with 2
2*(4x-2+7x+9) = 300 solve inside the parenthesis
2*(11x+7) = 300 multiply inside the parenthesis with 2
22x + 14 = 300 subtract 14 from both sides
22x = 286 divide both sides by 22
x = 13
