This is a direct variation, since the cost and the number of articles purchases both go up.
Step-by-step explanation:
5/8 × 6/8= 30/8 => this is the wrong one
it should be 5/8 × 6/8= 30/64.
9/10×3/10= 27/100 => this is the true one
When you move the 40 to the other side ur subtracting and so -40 - 5 is -45, after you divide -45 and 5 and get -9.
Step 1; multiple equation 2 by -2: 14x+8y=-18
step2: subtract this new equation from equation 1 to eliminate x:
2y-8y=18-(-18)
-6y=36
y=-6
step 3: substitute y=6 in equation 2: -7x-4*(-6)=9, -7x=-15, x=15/7