The answer to the question is -50
You use subtraction in this operation:
70 seashells - 19 seashells = 51 seashells
Thus, Joan is given 51 seashells.
Answer:

Step-by-step explanation:
Given
The attached triangle
Required
Determine the value of x
x represents the height of the triangle.
And the area of a triangle is calculated as:

Where



The expression becomes



Divide through by 2

