Answer:
Cross Multiply
Step-by-step explanation:
Cross multiplication can help answer these questions.
a. 3x-4/8=x+2/3
step 1- multiply 8 and (x+2), and 3 and (3x-4)
8x+16=9x+12
step 2- Subtract 8x on both sides
16=x+12
step 3- subtract 12 on both sides
4=x, or x=4
b. 3(2-r)/4=3+r/6
step 1- open parentheses
3(2-r)=6-3r
6-3r/4=3+r/6
step 2- cross multiply (put them into a equation without fractions by cross multiplying)
(6-3r) · 6= (3+r) ·4
step 3- multiply
36-18r=12+4r
step 4- solve
add 18r on both sides
36=12+22r
subtract 12 from both sides
24=22r
divide by 22 on both sides
24/22 or 12/11=r
r=12/11
c. 4p+3/8=p+2/4
step 1- cross multiply
(4p+3) · 4= (p+2)·8
step 2- open the parentheses
16p+12=8p+16
step 3- solve
subtract 12 on both sides
16p=8p+4
subtract 8p on both sides
8p=4
divide by 8 on both sides
p=4/8, or p=1/2
d. 2(a-7)/15=a+4/6
step 1- open parentheses
2(a-7) = 2a-14
2a-14/15=a+4/6
step 2- cross multiply
(2a-14) · 6 = (a+4) · 15
step 3- open parentheses
12a-84=15a+60
step 4- solve
subtract 60 on both sides
12a-144=15a
(the answer is -144 because a negative minus a negative such as -80-60=-144.
subtract 12a on both sides
-144=3a
divide by 3 on both sides
-48=a, or a=-48
