Solving More Equations Involving Two Operations

C7.5

Solving more equations involving two operations

To keep the equation balanced, we need to perform the inverse operation on both sides of the equation. Theorder in which we perform each inverse operation is important.

Solve each of the following equations.

(a) – 8 = 3(b) = 3

(a) – 8 = 3[undo – 8 by using + 8]

– 8 + 8= 3 + 8

= 11

 7= 11  7[undo  7 by using  7]

a= 77

(b) = 3[undo  7 first by using  7]

 7= 3  7

b – 8= 21

b – 8 + 8= 21 + 8 [undo – 8 by using + 8]

b= 29

1Solve each of the following equations.

(a) + 4 = 5

First, undo + 4 by using …… + 4 – 4= 5 – 4

= 1

Next, undo  2 by using …… 2= 1  2

x= ……

C7.5 (continued)

(b) – 8 = 22

First, undo …… by using + 8 – 8 ……= 22……

= 30

Next, undo …… by using  3 3= 30  3

x = ……

First, swap so the pronumeral term is first. + 16= 19

Then, undo …… by using …… + 16……= 19……

= 3

Next, undo  4 by using …… ……= 3  ……

y= ……

(d)8 + = 5

First, swap so the pronumeral term is first. + 8= 5

Then, undo …… by using …… + 8……= 5……

= -3

Next, undo …… by using  3 3= -3  3

x= ……

(e)20 = 25 + (f)17 = 30 +

2Solve each of the following equations.

(a) = 5(b) = 22(c) = 19