Three triangles and four circles are equal to 17, three triangles and one circle is equal to 11
Let the triangle be x and the circle be y. we know that 3x + 4Y = 17,3x + y = 11. We can solve the linear equations of two variables with x = 3, y = 2
So triangle is 3, circle is 2, a triangle is 3 + 2 = 5