Firstly, a key fact to keep in mind is Angles in a triangle equals 180⁰.
a. x+60⁰+30⁰=180⁰
x+90⁰=180⁰
x=180⁰-90⁰
x=90⁰
b. x+3x+40⁰=180⁰
collect like terms
4x+40⁰=180⁰
4x=180⁰-40⁰
4x=140⁰
Divide both sides by 4
x=35⁰
c. x+(x+7)+(x+5)=180⁰
3x+12=180⁰
3x=180⁰-12
3x=168⁰
x=168⁰÷3
x=56⁰
d. 52+x+y=180⁰
keeping in mind, two sides of this triangle are equal...
180⁰-52⁰=128⁰
128⁰÷2=64⁰
x=64⁰
x=64⁰ y=64⁰
e. b+a+90⁰=180⁰
right angled triangle
180⁰-90⁰=90⁰
90⁰÷2=45⁰
b=45⁰
b=45⁰ a=45⁰
f. Angles on a straight line equals 180⁰
180⁰-130⁰=50⁰
x=50⁰
Back to the triangle, in which two are equal,
50⁰+x+y=180⁰
180⁰-50⁰=110⁰
110⁰÷2=55⁰
y=55⁰
y=55⁰ z=55⁰
To be honest, I don't know how to solve the last two questions, hope I was helpful, if you wish, please mark BRAINLIEST.
