ten times a number. we'll call "a number" x:
[tex]10 * x[/tex]
ten times a number increased by four. increased by is a fancy way of saying plus:
[tex]10 * x + 4[/tex]
ten times a number increased by four is no more than twenty five. if a number is no more than 25, that means it's either less than 25 or equal to 25. so:
[tex]10 * x + 4 \leq 25\\10x+4 \leq 25[/tex]
