[tex] \qquad\large\boxed{ \underbrace{ \mathbb{ANSWER}}}[/tex]
We are given an expression with a variable and the value of the variable is given. We just have to substitute the variable with the given value and solve...
[tex]\blue{⊱─━━━━━━━━⊱༻●༺⊰━━━━━━━━─⊰}[/tex]
[tex] \tt \: 4(10-r)[/tex]
[tex] \bf \: 4 \times (10-3)[/tex]
[tex] \bf \: 4\times 7[/tex]
[tex] \bf \underline{ \underline{28}}[/tex]
