No 1; Let the number be y. Six times a number y, means six times y, or better put,
6 * y = 6y
15 less than (six times a number y) 6y now becomes
Deduct/subtract 15 from 6y
6y - 15
No 2; The inequalty
x ≥ 3.25
Can be interpreted as;
"x is greater than and as well equal to 3.25." This simply means x can take the value of 3.25, and then any number greater than that. Therefore, x can be equal to 3.25, 4, and 5.
No 3; Simplify 8 (4x + 12)
The value 8 will effectively multiply all other values within the parenthesis, and you now have,
32x + 96
No 4; Evaluate 4 (3^2 - 5) + 17
4 (9 - 5) + 17
The number 4 multiplies other values in the parenthesis and you now have
4(4) + 17
16 + 17
33