the 2 equations that need to be solved are [3x+5] and x-1. If you need the answer to what x is you'd solve it by evening out the problems. so first add one to both so you'd have 3x+6=x then you'd take the 3x and subtract it from both sides making it 6=-2x. Then divide 6 by negative 2 making it -3=x.
D - 90 because 20 x 30 and multiply by 0.15
For the answer tot he question above, let the number of t-shirts are represented by 't'
number of sweaters are represented by 's'
cost of 1t=10 and cost of 1s=20 so
10t+20s=2000 or (factor out the 10 if you want to simplify)
10(t+2s)=10(200)
divide both sides by 2
t+2s=200
Answer:$3750
Step-by-step explanation: