Remark
You need to do the bottom left to the upper right.
And then you need to do top left to bottom right.
Cross multiply
2. 7 * 3 = 5*x Combine the left
21 = 5x Divide by 5
21 / 5 = x
x = 4 1/5
x = 4.2
4.
7 * 7 = 8n combine the left
49 = 8n Divide by 8
49/8 = n
n = 6 1/8
n = 6.125
6 This one is a bit harder. But the rules are the same.
7*5 = 10*(b + 5) Notice you put brackets around b + 5
35 = 10b + 50 The plus remains. The 10 multiplies both the b and the 5
35 - 50 = 10b You have subtracted 50 from both sides.
- 15 = 10b Divide by 10
- 15/10 = b
b = - 1.5 This is a good question to study.