How to index in for loop

I have a an array

a=[4 9 7]

A Matrix

 b= [5 7;4 2]; 

I want to have

c1=4*b c2=9*b; c3=7*b

. I want to use c1,c2"c3' later as d1=r-c1*x; d2=r-c2*x; Where r=[4;9]; x=[3 5]

[rakesh kumar]

x=[3;5]

Answer 1

[David Hill]

for k=1:length(a)
  c(:,:,k)=a(k)*b;%index instead of having different variables
  d(:,:,k)=r-c(:,:,k)*x;
end

[rakesh kumar]

Thanks david, thanks a lot