We refine a recent result of Parsell on the values of the form λ1​p1​+λ2​p2​+μ1​2m1​+...m+μs​2ms​, where p1​,p2​ are
prime numbers, m1​,...c,ms​ are positive integers, λ1​/λ2​
is negative and irrational and λ1​/μ1​, \lambda_2/\mu_2 \in \Q.Comment: v2: enlarged introduction, improved major arc estimat