50 points 7th grade math ! asap

1. sam solved the following problem:

-4x + 5 > 29
-4x + 5 - 5 > 29 - 5
-4x > -24
-4x/-4 > -24/-4
x > 6

what were his two mistakes? (3 points)

2. hillary buys 3 pounds of gala apples and some granny smith apples. both kinds of apples cost $4.50 per pound. the total cost is $24.75. how many pounds of granny smith apples did hillary buy? write and solve a variable equation. show your work.
(4 points)

3. tell whether each equation has one solution, infinitely many solutions, or no solution. (3 points)

6x + 8 = 6(x + 2)
10x = 15 + 5x
x + 11 = 8x + 11 - 7x

Which expression can be used to determine the slope of the line that passes through the points -6, three and one, -9

Me find the value of x each figure.

Aspacecraft can attain a stable orbit 300 kilometers above earth if it reaches a velocity of 7.7 kilometers per second. the formula for a rocket's maximum velocity v in kilometers per second is vequalsminus0.0098tplusc ln upper r, where t is the firing time in seconds, c is the velocity of the exhaust in kilometers per second, and r is the ratio of the mass of the rocket filled with fuel to the mass of the rocket without fuel. find the velocity of a spacecraft whose booster rocket has a mass ratio of 20, an exhaust velocity of 2.1 km/s, and a firing time of 15 s. can the spacecraft achieve a stable orbit 300 km above earth?