Question

Solve [a] 7x + 10 = 80 [b] 2x = 30

Answer 1

[a] 7x + 10 = 80

⟹ 7x = 80 - 10

⟹ 7x = 70

⟹ x = 70/7

⟹ x = 10

[b] 2x = 30

⟹ x = 30/2

⟹ x = 15

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Answer 2

${ \sf { \bold{[a] \: 7x + 10 = 80}}}$

$\leadsto{ \sf { \: 7x + 10 = 80}}$

Subtract 10 from both the sides. Now,

$\leadsto{ \sf { \: 7x + 10 - 10 = 80 - 10}}$

$\leadsto{ \sf { \: 7x = 70}}$

Then, divide by 7 both the sides. Now,

$\leadsto{ \sf { \: \frac{ \cancel7x}{ \cancel7} = \frac{ \cancel{7 0} }{ \cancel7} }}$

$\leadsto{ \red{ \sf{ \bold{x = 10}}}} \: \bigstar$

_____________________

${ \sf{\bold{[b] \: 2x = 30}}}$

$\leadsto{ \sf{x = \frac{30}{2}}}$

$\leadsto{ \sf{x = \cancel\frac{30}{2}}}$

$\leadsto{ \red{ \sf{ \bold{x = 15}}}} \: \bigstar$