I estimated to 45 then divided 21 and got about 2.1

m is the slope
b is the y-intercept
so that means that the y-intercept of

is

Well to solve for x you simply need to multiply both sides of the equation to isolate x, the answer will be x=34. the second question requires bedmas (brackets, exponents, division and multiplication, addition and subtraction)
It will be 224 no matter if you multiply or divide first
The Martin family can drive 99 miles using 3 gallons of gas