Answer:
b=9,a=12
Step-by-step explanation:
I solved by substitution:
b = 3/4a ---> plug this into the other equation
a + b = 21 is now a + 3/4a = 21
Reduce: 7/4a = 21
a = 12
Now solve for b:
b=3/4a is now b=3/4(12)
b=9
15×30=450cm^3 I hope this helps you. A=l×w
Let l represent length, and w represent width
l=3w-5
P=2(l+w)
46=2(l+w)
Divided 2 for both side
l+w=23
Now, I substitute l=3w-5 into this equation
3w-5+w=23
4w-5=23
Add 5 for both side
4w=28
Divided 4 for both side
w=7 inches
l=3w-5
l=3(7)-5
l=21-5
l=16 inches. As a result, the length is 16 inches, and the width is 7 inches. Hope it help!